public String breed; public String color; // 메소드정의 public void bark()... public void bite()... public void eat()... // 종 // 색깔 p 기초변수는 int, flo

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1 p 객체 , SIMULA p 데이터, 알고리즘 2. 데이터 3. 클래스를변경하기가쉬워진다. p 메시지 2. start(), stop(), speedup(int s), speeddown(int s), turnleft(int degree), turnright(int degree) p 클래스 2. 변수는공유되지않는다. 즉변수는각객체마다하나씩생성된다. 하지만메소드는공유된다. 3. 필드, 메소드 4. 도트 (.) 5. 필드 6. class Stock() // 필드정의 public int num; // 상품번호 public int count; // 메소드정의 public void stockup() count++; public void stockdown() count--; 7. class Dog() // 필드정의 public String name; // 재고수량 // 이름

2 public String breed; public String color; // 메소드정의 public void bark()... public void bite()... public void eat()... // 종 // 색깔 p 기초변수는 int, float, char 등의기초자료형을가지는변수이고, 참조변수는객체를참조할때사용되는변수이다. 2. 두개의참조변수가하나의객체를가리킨다. 3. 참조변수에 null 을대입한다. 예를들면 p = null; 와같다. p 기초형, 참조형 2. new 3. String 4. length() 5. + class BankAccount // 은행계좌 int balance; // 잔액을표시하는변수 void deposit(int amount) // 저금 balance += amount; void withdraw(int amount) // 인출 balance -= amount; int getbalance() // 잔고반환 return balance; public class BankAccountTest public static void main(string[] args) BankAccount b = new BankAccount();

3 (1) BankAccount b = new BankAccount(); b.balance = 100; b.withdraw(60); System.out.println(b.getBalance()); (2) void addinterest() balance = balance + balance*0.075; (3) void withdraw(int amount) // 인출 if( amount < 0 ) return; balance -= amount; (4) 하나의소스파일안에는한개의 public 클래스만이있어야한다. 원칙적으로 public 클래스들은별도의소스파일안에정의하여야한다. 1. class NumberBox public int ivalue; public float fvalue; public class NumberBoxTest public static void main(string[] args) NumberBox b = new NumberBox(); b.ivalue=10; b.fvalue=(float)1.2345; System.out.println(b.ivalue); System.out.println(b.fvalue); 2. 상태 ( 속성 ) 변수 int year int month int day 설명년도월일

4 동작 ( 행동 ) 메소드이름 void setdate(int y, int m, int d) void printdate() 3. 객체가생성되지않았다. new 를이용하여서객체를생성해준다. class Rectangle int width, height; int area() return width*height; public class Test public static void main(string[] args) Rectangle myrect; myrect = new Rectangle(); myrect.width = 10; myrect.height = 20; System.out.println(" 면적은 " + myrect.area()); 4. (a) 생각이현실이된다 (b) 문자열의길이는 7 (c) ABCDEFG (d) = 5 (e) = 23 설명날짜를설정날짜를출력 1. class Rectangle int w; int h; int area() return w*h; int perimeter() return 2*(w+h); public class RectangleTest public static void main(string[] args) Rectangle myrect; myrect = new Rectangle(); myrect.w = 10; myrect.h = 20; System.out.println(" 면적은 " + myrect.area());

5 2. class Date int year; int month; int day; void print1() System.out.println(year + "." + month + "." + day); public class DateTest public static void main(string[] args) Date d; d = new Date(); d.year = 2012; d.month = 9; d.day = 5; d.print1(); 3. class ComplexNumber int real; int imag; void print() System.out.println(real + "+ i" + imag); public class ComplexNumberTest public static void main(string[] args) ComplexNumber c; c = new ComplexNumber(); c.real = 10; c.imag = 20; c.print(); 4. class Movie int year; String title; void print()

6 System.out.println(year + ": " + title); public class MovieTest public static void main(string[] args) Movie m; m = new Movie(); m.year = 2012; m.title = "Total Recall"; m.print(); 5. import java.util.scanner; public class StringTest public static void main(string[] args) String s; Scanner sc = new Scanner(System.in); System.out.println(" 문자열을입력하시오 : "); s = sc.next(); for(int i=0;i<s.length();i++) System.out.print(s.charAt(s.length()-1-i)); 6. import java.util.*; public class ConVo public static void main(string[] args) String s; char s2; int count1 = 0, count2 = 0; Scanner scan = new Scanner(System.in); System.out.print(" 문자열을입력하세요 : "); s = scan.next(); for(int i = 0; i < s.length(); i++) s2 = s.charat(i); if((s2 >= 'A' && s2 <= 'Z') (s2 >= 'a' && s2 <= 'z')) if(s2=='a' s2=='e' s2 == 'i' s2 == 'o' s2 == 'u') count1++; else count2++; System.out.println(" 자음의개수 : " + count2); System.out.println(" 모음의개수 : " + count1); 7.

7 import java.util.*; public class Password public static void main(string[] args) String s; String id="abcdef"; Scanner scan = new Scanner(System.in); System.out.print(" 아이디를입력하세요 : "); s = scan.next(); if( s.equalsignorecase(id) ) System.out.println(" 로그인이성공하였습니다 "); else System.out.println(" 로그인이실패하였습니다 "); p 크게나누면기초형변수와참조형변수가존재한다. 2. 잘못된값이저장되는것은사전에체크할수있고또필요할때마다값을다시계산하여서반환할수도있다. 3. 필드는클래스안에선언되는변수이다. 지역변수는메소드안에선언되어서메소드안에서만사용되는변수이다. p 중복메소드 (overloading method) 2. 값을반환하지않는메소드를나타낸다. 3. public void printmyname() String name; System.out.println(" 이름을입력하시오 :"); Scanner scan = new Scanner(System.in); name = scan.nextline(); System.out.println(name); p.187

8 1. TV -ison : bool -channel: int +turnon() +turnoff() +setchannel(int) +getchannel(); int 1. (1) class Box // 필드정의 int width; int length; int height; // 메소드정의 (2) class Box public int getwidth() return width; public void setwidth(int width) this.width = width; public int getlength() return length; public void setlength(int length) this.length = length; public int getheight() return height; public void setheight(int height) this.height = height; // 필드정의 int width; int length; int height; // 메소드정의 (3) public int getvolume()

9 (4) return width*length*height; public void print() System.out.println(" 가로 :" + width); System.out.println(" 세로 :" + width); System.out.println(" 높이 :" + width); (5) public class BoxTest public static void main(string[] args) (6) (7) (8) Box box1; box1 = new Box(); box1.setwidth(100); box1.setlength(100); box1.setheight(100); System.out.println(box1.getVolume()); (9) (10) 가로 :200 세로 :200 높이 :200 Box box2; box2 = new Box(); box2.setwidth(200); box2.setlength(200); box2.setheight(200); box1 = box2; box1.print(); 1. 설정자에서매개변수를통하여잘못된값이넘어오는경우, 이를사전에차단할수있다. 필요할때마다필드값을계산하여반환할수있다. 접근자만을제공하면자동적으로읽기만가능한필드를만들수있다. 2. class Television

10 private String model; void setmodel(string b) // 설정자 model = b; String getmodel() // void->string return model; public class TelevisionTest public static void main(string[] args) Television t = new Television(); // () 을붙여주어야함! t.setmodel("stv-101"); String b = t.getmodel(); // 객체참조변수 t 를적어주어야함. 3. (1) public String gettitle() return title; public void settitle(string title) this.title = title; public String getdirector() return director; public void setdirector(string director) this.director = director; public String getactors() return actors; public void setactors(string actors) this.actors = actors;

11 (2) Movie -title : String -director : String -actor : String +gettitle() +getdirector() +getactor() +settitle() +setdirector() +setacotr() (3) public class Movie private String title, director, actors; public String gettitle() return title; public void settitle(string title) this.title = title; public String getdirector() return director; public void setdirector(string director) this.director = director; public String getactors() return actors; public void setactors(string actors) this.actors = actors; (4) Movie m = new Movie(); m.settitle("transformer"); 4. (1) 은행, 정기예금계좌, 보통예금계좌, 고객 (2) SavingsAccount, CheckingAccount, Customer (3) Account: 계좌번호, 소유자이름, 잔액, deposit(), withdraw() SavingsAccount extends Account: 이자율, 이자계산 () CheckingAccount extends Account: 카드번호 ( 수표번호 ), 부도여부 Customer: 이름, 주소, 소유한계좌번호

12 class Account String AccNumber; String ownername; int balance; void deposit(int amount) balance += amount; void withdraw(int amount) if (balance > amount) balance -= amount; class CheckingAccount extends Account String cardnumber; boolean status; 1. Circle -r : double -cx : double -cy : double +area() +setr() +setcx() +setcy() +getr() +getcx() +getcy() class Circle double r; double cx; double cy; public double area() return *r*r; public double getr() return r; public void setr(double r) this.r = r;

13 public double getcx() return cx; public void setcx(double cx) this.cx = cx; public double getcy() return cy; public void setcy(double cy) this.cy = cy; public class CircleTest public static void main(string[] args) Circle c = new Circle(); c.setr(10.0); System.out.println(c.area()); 2. class Book private String title, author; public String gettitle() return title; public void settitle(string title) this.title = title; public String getauthor() return author; public void setauthor(string author) this.author = author; public class BookTest public static void main(string[] args) Book b = new Book(); b.settitle("data structure"); b.setauthor(" 홍길동 ");

14 3. class Dice private int face; int roll() int face = (int)(math.random() * 6) + 1; return face; public class DiceTest public static void main(string[] args) Dice dice = new Dice(); System.out.println(" 주사위숫자 : " + dice.roll()); 4. class Point int x, y; public void set(int x, int y) this.x = x; this.y = y; public void print() System.out.println("("+x+","+y+")"); public class PointTest public static void main(string[] args) Point p = new Point(); p.set(10, 10); p.print(); 5. class Employee private String name; private int tel; private int sal; public void setname(string n) name = n; public void settel(int t) tel = t; public void setsal(int s) sal = s;

15 public String getname() return name; public int gettel() return tel; public int getsal() return sal; public class EmployeeTest public static void main(string[] args) Employee em = new Employee(); 6. class BankAccount int accountnumber; String owner; int balance; void deposit(int amount) balance += amount; void withdraw(int amount) balance -= amount; public String tostring() return " 현재잔액은 " + balance + " 입니다."; public int transfer(int amount, BankAccount otheraccount) otheraccount.deposit(amount); return (balance-amount); public class BankAccountTest public static void main(string[] args) BankAccount myaccount1 = new BankAccount(); BankAccount myaccount2 = new BankAccount(); myaccount1.deposit(10000); System.out.println("myAccount1 : " +myaccount1); myaccount1.withdraw(8000); System.out.println("myAccount1 : " + myaccount1); System.out.println("myAccount2 : " + myaccount2); int b = myaccount1.transfer(1000, myaccount2); myaccount1.withdraw(b); System.out.println("myAccount1 : " + myaccount1); System.out.println("myAccount2 : " + myaccount2); 7. class Average public int getaverage(int a, int b) return (a+b)/2; public int getaverage(int a, int b, int c) return (a+b+c)/2;

16 public class AverageTest public static void main(string[] args) Average a = new Average(); System.out.println(a.getAverage(10, 20)); System.out.println(a.getAverage(10, 20, 30)); p MyClass 2. 생성자는반환형이없다. 3. 기존생성자호출 p 정적변수는클래스의모든객체들에의해공유될때사용하는것이좋다. 2. 정적변수와정적메소드는객체를생성할필요가없고매개변수를통하여전달된값만있으면되므로클래스이름을통하여접근한다. 3. main() 메소드도정적메소드이기때문 p 필드를다른클래스가직접사용하지못하게하기위해서 2. 디폴트로 package 가된다. 즉같은패키지에속하는클래스들은자유롭게사용할수있다. p 자기자신을참조하는데사용된다. 2. 자신의생성자호출한다. p 사용관계는하나의클래스가다른클래스를사용하는것이고, 집합관계는하나의클래스가다른클래스를포함하는것이다.

17 1. public class Circle private double radius; static final double PI= ; // PI 라는이름으로 로초기화된정적상수 (1) public Circle(double r) radius = r; (2) public double getradius() return radius; public void setradius(double radius) this.radius = radius; (3) private double square(double value) return value*value; (4) public double getarea() return square(radius)*pi; (5) public double getperimeter() return 2.0*PI*radius; (6) public static double getpi() return PI; (7) square() 함수는정적함수가아니라서 main() 에서호출하면오류가발생한다. (8) getpi() 함수는정적함수이므로 main() 에서호출할수있다. (9) class Circle private double radius; static final double PI= ; // PI 라는이름으로 로초기화된정적상수 public Circle(double r) radius = r;

18 public double getradius() return radius; public void setradius(double radius) this.radius = radius; private double square(double value) return value*value; public double getarea() return square(radius)*pi; public double getperimeter() return 2.0*PI*radius; public static double getpi() return PI; public class CircleTest public static void main(string args[]) Circle c = new Circle(5.0); // 객체생성, 생성자호출시반지름을 5.0 으로설정 System.out.println(c.getArea());// 원의면적계산하여출력 System.out.println(c.getPerimeter());// 원의둘레계산하여출력 1. (1) 객체가생성될때에필드에게초기값을제공하고필요한초기화절차를실행 (2) 매개변수의자료형이나매개변수개수로구별되어호출 (3) 자기자신을참조 (4) 정적변수는하나의클래스에하나만존재하여그클래스의모든객체들에의해공유되지만인스턴스변수는각인스턴스마다별도로생성된다. (5) 객체의참조값이전달된다. (6) 정적메소드는객체가생성되지않은상태에서호출되는메소드이므로객체안에서존재하는인스턴스변수들은사용할수없다. 2. (1) 생성자 Point() 는값을반환하지않는다따라서 void 를삭제한다. (2) 메소드의반환형이다르다고해서메소드를중복시킬수있는것은아니다. class MyMath public int getrandom1() return (int)math.random(); public double getrandom() return Math.random();

19 (3) 정적메소드 getstringname() 에서인스턴스메소드 getname() 을호출할수없다. class MyClass private static String getname() return "Myclass"; public static String getclassname() return getname(); 3. (1) public class Cube private double side; public Cube() side = 0; public double getside() return side; public double getvolume() return side*side*side; (2) public class Cube private double side; public Cube() side = 0; public Cube(double side) this.side = side; public double getside() return side; public double getvolume() return side*side*side; // 정육면체의한변 // 정육면체의한변 4. class MyMetric private static double distance; public static double kilotomile(double d) distance = d / ; return distance; public static void miletokilo(double d) distance = d * ;

20 public class MyMetricTest public static void main(string args[]) double d = MyMetric.kiloToMile(1); System.out.println(d); 5. s_instance 가 null 일때만객체를생성하고이미객체가생성되어있으면단순히객체의참조값을반환한다. class Single private static Single s_instance; public static Single getinstance() if (s_instance == null) s_instance = new Single(); return s_instance; 1. Dog -name : String -breed : String -age : int +getname() +getbreed() +getage() +setname() +setbreed() +setage() public class Dog private String name; private String breed; private int age; public Dog(String name, int age) this.name = name; this.age = age; public Dog(String name, String breed, int age) this.name = name; this.breed = breed;

21 this.age = age; public String getname() return name; public String getbreed() return breed; public int getage() return age; public void setname(string n) name = n; public void setbreed(string b) breed = b; public void setage(int a) age = a; 2. class Plane private int num, p_num; private String model; private static int planes; public void setnum(int n) num = n; public void setpnum(int pn) p_num = pn; public void setmodel(string m) model = m; public int getnum() return num; public int getpnum() return p_num; public String getmodel() return model; public static void setplanes(int p) planes = p;

22 public static int getplanes() return planes; public Plane() public Plane(int n, String m, int pn) num = n; p_num = pn; model = m; public Plane(int n, String m) num = n; model = m; public String tostring() return " 식별번호 :" + getnum() + " 모델 : " + getmodel() + " 승객수 : " + getpnum(); public class PlaneTest public static void main(string[] args) Plane plane1 = new Plane(1, "aa", 200); Plane plane2 = new Plane(2, "bb"); Plane plane3 = new Plane(); plane1.setplanes(0); plane1.getplanes(); plane3.setnum(3); plane3.setmodel("cc"); plane3.setpnum(150); 3. public class Box private int width, length, height; private boolean empty = false; public int getwidth() return width; public void setwidth(int width) this.width = width; public int getlength() return length; public void setlength(int length) this.length = length; public int getheight() return height; public void setheight(int height)

23 this.height = height; public boolean isempty() return empty; public void setempty(boolean empty) this.empty = empty; public Box() width = 0; length = 0; height = 0; empty = true; public Box(int w, int l, int h) width = w; length = l; height = h; empty = true; 4. public class Movie private String title; private String direction; private String company; public Movie() public Movie(String t, String d, String c) title = t; direction = d; company = c; 5. public class BankAccount private String ownername; private int accountnumber; private int balance; private double rate; public String getownername() return ownername; public void setownername(string ownername) this.ownername = ownername; public int getaccountnumber() return accountnumber;

24 public void setaccountnumber(int accountnumber) this.accountnumber = accountnumber; public int getbalance() return balance; public void setbalance(int balance) this.balance = balance; public double getrate() return rate; public void setrate(double rate) this.rate = rate; public BankAccount() public BankAccount(String n, int a, int b, double r) ownername = n; accountnumber = a; balance = b; rate = r; p int[] array = new int[100]; 2. 0 에서 9 사이의정수 3. 예외 ( 오류 ) 가발생한다. 4. double[] array = 1.2, 3.1, 6.7 ; 5. for(i=0;i<array.length;i++) array[i] = 2 * array[i]; 6. Scanner scan=new Scanner(System.in); System.out.println( 배열의크기 : );

25 int size = scan.nextint(); int[] array = int[size]; 7. for-each 와전통적인 for 루프를비교하라. for-each 루프는배열의크기에신경쓰지않아도되고인덱스변수를생성할필요없이배열의첫번째원소부터마지막원소의값을꺼내서처리하는경우에사용한다. 하지만역순으로배열원소를처리하거나일부원소만처리하는경우는 for 루프를사용한다. 전통적인 for 루프를사용하면배열의원소를변경할수있지만 for-each 보다불편할수있다. 뒤에서학습하는컬렉션에서는 for-each 구조가무척편리하다. 8. 배열의크기가동일하다고가정하자. for(i=0;i<length;i++) array2[i] = array1[i]; 9. 배열의참조값이전달된다. 10. 배열원소는값이전달되고배열은참조가전달된다. p BankAccount[] bank = new BankAccount[3]; for(int i =0; i < bank.lengh; i++) bank[i] = new BankAccount(); 2. 참조값이전달된다. p Book[][] library = new Book[8][100]; 2. 2 차원배열객체를가리키는참조값이전달된다. 1. class Employee String name; // 직원의이름 public String getname() return name; public void setname(string name) this.name = name; public String getaddress() return address; public void setaddress(string address) this.address = address; public int getsalary() return salary;

26 2. public void setsalary(int salary) this.salary = salary; public String getphone() return phone; public void setphone(string phone) this.phone = phone; String address; // 주소 int salary; // 연봉 String phone; // 전화번호 import java.util.scanner; class Employee String name; // 직원의이름 public String getname() return name; public void setname(string name) this.name = name; public String getaddress() return address; public void setaddress(string address) this.address = address; public int getsalary() return salary; public void setsalary(int salary) this.salary = salary; public String getphone() return phone; public void setphone(string phone) this.phone = phone; String address; // 주소 int salary; // 연봉 String phone; // 전화번호

27 public class EmployeeTest public static void main(string args[]) Scanner scan = new Scanner(System.in); // 크기가 3 인 Employee 의배열 employees 을생성한다. Employee[] employees = new Employee[3]; // 3 명의사원정보를받아서각각 Employee 객체를생성한후에배열에추가하여본다. 반복루프를사용한다. for (int i = 0; i < employees.length; i++) employees[i] = new Employee(); for (int i = 0; i < employees.length; i++) System.out.println(" 이름 : "); employees[i].name = scan.next(); System.out.println(" 주소 : "); employees[i].address = scan.next(); // employees 배열에저장된모든데이터를출력한다. 반복루프를사용한다. for (int i = 0; i < employees.length; i++) System.out.println(" 이름 : " + employees[i].name); System.out.println(" 주소 : " + employees[i].address); 1. (1) int[] studentnumbers = new int[30]; (2) double[] values = 1.2, 3.3, 6.7; 2. (1) int[] numbers = new int[100]; (2) double[] rainfalls = new double[100]; 3. (1) 0 부터 4 까지 (2) 실시간오류발생 4. for(int i = 0; i < values.length; i++) values[i] = 0; 5. int[] a = 1, 2, 3, 4, 5; int[] b = new int[5]; for(int i = 0; i < a.length; i++) b[i] = a[i];

28 6. String[] employees = new String[10]; String name = " 홍길동 "; employees[0] = name; name = null; 배열의원소중에서 0 번째를제외하고나머지원소들은초기화가안되었다. 따라서 9 개의 null 참조가배열 employees[] 안에존재한다. 1. import java.util.scanner; class Theater int[] seats; int size; public Theater(int size) this.size=size; seats = new int[size]; public void print() System.out.println(" "); for(int i=0; i<size; i++) System.out.print(i+" "); System.out.println("\n "); for(int i=0; i<size; i++) System.out.print(seats[i]+" "); System.out.println("\n "); public void reserve() System.out.println(" 몇번째좌석을예약하시겠습니까?"); Scanner scan = new Scanner(System.in); int s = scan.nextint(); if( seats[s] == 0 ) seats[s] = 1; System.out.println(" 예약되었습니다."); public class TheaterTest public static void main(string args[]) Theater t = new Theater(10); t.print(); t.reserve(); t.print();

29 2. import java.util.scanner; class Histogram int[] freq; int size; public Histogram(int size) this.size = size; freq = new int[size]; public void print() for(int i=0; i<size; i++) System.out.print((i*10+1)+"-"+(i+1)*10); for(int k=0; k<freq[i]; k++) System.out.print("*"); System.out.println(""); public void input() System.out.println(" 점수를입력하시오 "); Scanner scan = new Scanner(System.in); int s = scan.nextint(); if( s!= 0 ) freq[(s-1)/10]++; else freq[0]++; public class HistogramTest public static void main(string args[]) Histogram t = new Histogram(10); for(int i=0;i<10;i++) t.input(); t.print(); 3. import java.util.scanner; public class ScoreTest static int[] num = new int[5]; static int sum =0; static double avg; public static void main(string[] args) Scanner s = new Scanner(System.in); for(int i=0; i<5; i++) System.out.println(" 성적을입력하세요 "); num[i] = s.nextint(); gettotal(); getaverage();

30 private static void getaverage() avg = sum / 5.0; System.out.println(" 평균 : "+avg); private static void gettotal() for(int i =0; i < 5; i++) sum += num[i]; System.out.println(" 합계 : "+sum); 4. import java.util.scanner; class Hexa2Bin String[] hexa2bin = "0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"; public void print(string s) for(int i=0;i<s.length();i++) char c = s.charat(i); int index = 0; if( c >='0' && c <='9') index = (c - '0'); if( c >='a' && c <='f') index = 10 + (c - 'a'); System.out.print(hexa2bin[index]+" "); System.out.print(""); public class HistogramTest public static void main(string args[]) Hexa2Bin t = new Hexa2Bin(); t.print("1abc"); p 컴퓨터가수퍼클래스, 데스크탑, 노트북, 태블릿이모두서브클래스가된다.

31 컴퓨터 데스크탑노트북태블릿 2. 상속은코드를재사용하며코드의중복을줄인다. p sleep() 과 eat() 가수퍼클래스에서만정의되므로코드가간결해진다. 2. class Box int width, length, height; public int calvolume() return width*height*height; class ColorBox extends Box String color; import java.util.scanner; class Human private String name; private int age; public String getname() return name; public void setname(string name) this.name = name; public int getage() return age; public void setage(int age) this.age = public String tostring() return "Human [name=" + name + ", age=" + age + "]"; public String getprofession() return "unknown";

32 public Human(String name, int age) super(); this.name = name; this.age = age; class Student extends public String tostring() return super.tostring() + "Student [major=" + major + "]"; public String getprofession() return "student"; String major; public Student(String name, int age, String major) super(name, age); this.major=major; public String getmajor() return major; public void setmajor(string major) this.major = major; public class StudentTest public static void main(string args[]) Student s1 = new Student(" 명진 ", 21, " 컴퓨터 "); Student s2 = new Student(" 미현 ", 22, " 경영 "); Student s3 = new Student(" 용준 ", 24, " 경제 "); 1. (1) Student, GraduateStudent (2) Student -number: int +name : String

33 GraduateStudent +lab : String (3) class Student public int getnumber() return number; public void setnumber(int number) this.number = number; public String getname() return name; public void setname(string name) this.name = name; private int number; public String name; public class GraduateStudent extends Student public String getlab() return lab; public void setlab(string lab) this.lab = lab; public String lab; (4) class Student public Student(int number, String name) super(); this.number = number; this.name = name;... private int number; public String name; public class GraduateStudent extends Student public GraduateStudent(int number, String name, String lab) super(number, name); this.lab = lab;

34 ... public String lab; (5) (1) private 멤버는접근할수없다. 2. (1) methodtwo() (2) methodfour() (3) methodone() 과 methodthree() 는컴파일오류를발생한다. 인스턴스메소드를정적메소드로재정의할수는없다. 그반대도마찬가지이다. 3. class Bike protected int gear; public int speed; public class MountainBike extends Bike public int seatheight; public MountainBike(int g) super(); gear=g; 4. 동물입니다 :Brave 사자입니다. 동물입니다 :UNKNOWN 사자입니다. 1. class Circle double radius; String color; public Circle(double radius) super(); this.radius = radius; public Circle() super();

35 this.radius = 0; public double getradius() return radius; public void setradius(double radius) this.radius = radius; public double getarea() return * radius * radius; class Cylinder extends Circle public Cylinder(double radius, double height) super(radius); this.height = height; public Cylinder() super(0); public Cylinder(double radius) super(radius); public double getvolume() return super.getarea() * height; public double getheight() return height; public void setheight(double height) this.height = height; double height; public class TestCylinder public static void main(string[] args) Cylinder obj1 = new Cylinder(); System.out.println(obj1.getHeight()); System.out.println(obj1.getRadius()); Cylinder obj2 = new Cylinder(5.0, 3.0); System.out.println(obj2.getHeight()); System.out.println(obj2.getRadius());

36 2. class Person public Person(String name, String address) super(); this.name = name; this.address = address; public Person(String name, String address, String phone) super(); this.name = name; this.address = address; this.phone = phone; public String getname() return name; public void setname(string name) this.name = name; public String getaddress() return address; public void setaddress(string address) this.address = address; public String getphone() return phone; public void setphone(string phone) this.phone = phone; String name; String address; String phone; class Customer extends Person public Customer(String name, String address, int customernumber, int mileage) super(name, address); this.customernumber = customernumber; this.mileage = mileage; public Customer(String name, String address, String phone) super(name, address, phone);

37 int customernumber; int mileage; public class Test public static void main(string[] args) class Shape protected int x, y; protected int w, h; public double getarea() return 0; public double getperimeter() return 0; class Triangle extends Shape int a, b, c; public Triangle(int a, int b, int c) super(); this.a = a; this.b = b; this.c = public double getarea() return 2.0 * w * public double getperimeter() return a + b + c; public class Test public static void main(string[] args)... 4.

38 Book -title -pages -writer +gettitle() +settitle() +getpages() +setpages() +getwriter() +setwriter() +tostring <- class Book private String title; private int pages; private String writer; Magazine -date +getdate() +setdate() +main() public Book(String title,int pages,string writer) this.title=title; this.pages=pages; this.writer=writer; public String gettitle() return title; public void settitle(string title) this.title=title; public int getpages() return pages; public void setpages(int pages) this.pages=pages; public String getwriter() return writer; public void setwriter(string writer) this.writer=writer; public String tostring() return " 책이름 : "+title+"\n 페이지수 : "+pages+"\n 저자 : "+writer; public class Magazine extends Book private String date; public Magazine(String title,int pages,string writer,string date) super(title,pages,writer);

39 this.date=date; public String tostring() return super.tostring()+"\n발매일 :"+date; public static void main(string[] args) Magazine 잡지A = new Magazine(" 잡지A",10," 기자A","2010년 2월 25일 "); Magazine 잡지B = new Magazine(" 잡지B",20," 기자B","2010년 3월 8일 "); System.out.println( 잡지 A.toString()); System.out.println( 잡지 B.toString()); 5. 음식을나타내는 Food 클래스를상속받아멜론을나타내는 Melon 클래스를작성. Food 클래스는칼로리, 가격, 중량등의정보를가진다. Melon 클래스는추가로경작농원정보를가진다. (UML 을그린다.) Melon_Test +main() : void class Food private int cal; private int cost; private int kg; Melon ->Food -info : string +getinfo() : string +setinfo() : void +tostring(): string // 필드데이터정의 Food -cal : int -cost : int -kg : int +getcal() : int +getcost() : int +getkg() : int +setcal() : void +setcost() : void +setkg() :void public Food(int cal, int cost, int kg) // 생성자매개변수존재 this.cal = cal; this.cost = cost; this.kg = kg; public Food() this.cal = 0; this.cost = 0; this.kg = 0; // 생성자 public void setcal(int cal) // 설정자. this.cal = cal; public void setcost(int cost) this.cost = cost; public void setkg(int kg)

40 this.kg = kg; public int getcal() // 접근자. return cal; public int getcost() return cost; public int getkg() return kg; class Melon extends Food //melon 클래스작성 Food 상속 private String info; // 필드정의 public Melon(int cal, int cost, int kg,string info) super(cal, cost, kg); this.info = info; public Melon() super(); info = "NULL"; //Food 상속생성자작성 //Food 생성자호출 public void setinfo(string info) // 설정자. this.info = info; public String getinfo() // 접근자. return info; public String tostring() return "Melon 의정보 \n 칼로리 : "+this.getcal()+"\n 가격 : "+ this.getcost()+"\n 중량 : "+this.getkg()+"\n 정보 "+this.getinfo(); public class Melon_Test public static void main(string[] args) // 드라이버클래스작성 Melon m1 = new Melon(124,21,2,"jjh_fram"); Melon m2 = new Melon(1,1,1,"0"); m2.setcal(100); m2.setcost(210); m2.setkg(21); m2.setinfo("jjh2_test"); System.out.println(m1+"\n"); System.out.println(m2); 6. class Phone public Phone(String maker, int price, int type) super(); this.maker = maker; this.price = price; this.type = type; public String getmaker() return maker; public void setmaker(string maker) this.maker = maker;

41 public int getprice() return price; public void setprice(int price) this.price = price; public int gettype() return type; public void settype(int type) this.type = type; protected String maker; protected int price; protected int type; class SmartPhone extends Phone public String getos() return os; public SmartPhone(String maker, int price, int type, String os, String version, int memory, boolean hascamera, boolean hasbluetooth) super(maker, price, type); this.os = os; this.version = version; this.memory = memory; this.hascamera = hascamera; this.hasbluetooth = hasbluetooth; public void setos(string os) this.os = os; public String getversion() return version; public void setversion(string version) this.version = version; public int getmemory() return memory; public void setmemory(int memory) this.memory = memory; public boolean ishascamera() return hascamera; public void sethascamera(boolean hascamera) this.hascamera = hascamera; public boolean ishasbluetooth() return hasbluetooth;

42 public void sethasbluetooth(boolean hasbluetooth) this.hasbluetooth = hasbluetooth; private String os; private String version; private int memory; private boolean hascamera; private boolean hasbluetooth; public class Test public static void main(string[] args) class Student private String name; private int number; private String major; private int grade; private int next_point; 같기에 //Student 클래스정의 // 필드데이터정의 // 이름, 학번, 전공, 학년, 학점 // 생성자정의 public Student(String name,int number,string major,int grade,int next_point) this.name = name; // 매개변수와필드데이터이름이 this.number = number; //this. 사용자신의클래스변수를참조 this.major = major; this.grade = grade; this.next_point = next_point; public Student() name = null; number = 0; major = null; grade = 0; next_point = 0; 저장 public String getname() // 접근자를설정한다. return name; // 외부서접근자를통해해당데이터 public int getnumber() return number; public String getmajor() return major; public int getgrade() return grade; public int getnext_point() return next_point; public void setname(string name) // 설정자정의 this.name = name; // 설정자를통해클래스데이터변경가

43 능 public void setnumber(int number) this.number = number; public void setmajor(string major) this.major = major; public void setgrade(int grade) this.grade = grade; public void setnext_point(int next_point) this.next_point = next_point; public String tostring() //tostring 재정의한다. 클래스정보를출력 return " 이름 :"+name+" 학번 :"+number+" 학과 :"+major+" 학년 :"+ grade+" 이수학점 :"+next_point; class undergraduate extends Student // 학부생클레스정의 Stduent 로부터상속받음. private String club; // 필드데이터정의 " 동아리이름 " // 생성자정의 public undergraduate(string name, int number, String major, int grade, int nextpoint, String club) super(name, number, major, grade, nextpoint); //super 통해부모클래스생성자호출 this.club = club; public undergraduate() super(); club = null; public void setclub(string club) this.club = club; public String getclub() return club; // 생성자설정 // 접근자설정 //tostring 재정의한다. 학부생클래스정보출력 public String tostring() return " 이름 :"+getname()+"/ 학번 :"+getnumber()+"/ 학과 :"+getmajor()+ "/ 학년 :"+getgrade()+"/ 이수학점 :"+getnext_point() + "/ 소속동아리 :"+club; class Graduate extends Student private String assistant ; // 교육조교 private boolean scholarship; // 장학금여부 // 생성자를정의한다. public Graduate(String name, int number, String major, int grade, int nextpoint,string assistant, int scholarship) super(name, number, major, grade, nextpoint); //super 사용부모클래스생성자호출 this.assistant = assistant; this.scholarship = ((scholarship == 1)? true:false); // 입력값을확인 //1일경우 true 그외일경우 false 저장 public Graduate() super(); assistant = null; scholarship = false;

44 public void setassistant(string assistant) this.assistant = assistant; public void setscholarship(boolean scholarship) this.scholarship = scholarship; public String getassistant() return assistant; public boolean getscholarship() return scholarship; // 설정자정의 // 접근자정의 //tostring 재정의대학원생클래스의정보를출력 public String tostring() return " 이름 :"+getname()+"/ 학번 :"+getnumber()+"/ 학과 :"+getmajor()+ "/ 학년 :"+getgrade()+"/ 이수학점 :"+getnext_point() + "/ 조교유형 :"+assistant+"/ 장학금여부 :"+((scholarship == true)? " 받음 ":" 못받음 "); public class student_test public static void main(string[] args) "); 가능. 출 ) 경변경 undergraduate ug1 = new undergraduate(" 갑 ",1000," 컴공 ",3,84," 날자날어 Graduate g1 = new Graduate(" 을 ", 100, " 전자공학 ", 2, 51," 교육조교 ",0); Graduate g2 = new Graduate(" 병 ", 100, " 세포생물 ", 2, 61," 연구조교 ",1); // 대학원생객체를두개생성 g1,g2 를통해참조 System.out.println(ug1); //ug1 이가르키는객체정보를출력 (tostring 호 ug1.setclub(" 돌고돌아 "); //ug1 이가르키는객체클럽설정자호출, 값변 ug1.setnext_point(87); System.out.println(ug1); //ug1 이가르키는객체학점설정자호출, 데이터 //ug1 이가르키를객체정보를출력 System.out.println(g1); //g1 이가르키를객체정보를출력 경 변경 g2.setgrade(3); g2.setnumber(102); //g2가가르키는객체학년설정자를호출, 값변 //g2가가르키는객체학번설정자를호출, 값 System.out.println(g2); //g2 의객체정보를다시출력

45 p 주로상속계층에서추상적인개념을나타내기위한용도로사용 2. 추상클래스는일반메소드도포함한다 3. 반드시추상메소드를구현해야한다. p 객체와객체사이의상호작용을위하여사용 2. 하나의클래스는여러개의인터페이스를동시에구현할수있다. 3. 선언할수없다. p 인터페이스도클래스와마찬가지로타입이라고생각할수있다. 따라서참조변수를정의하는데사용될수있다 2. 여러클래스에서사용되는상수를정의하면그인터페이스를구현하는클래스들은자동적으로인터페이스에정의된상수들을공유하게된다. 3. 인터페이스를사용하여다중상속의효과를낸다. p 수퍼클래스참조변수가서브클래스객체를참조하는것은가능하지만, 서브클래스의참조변수가수퍼클래스의객체를참조하는것은문법적인오류이다. 2. A instanceof B 일때, 객체 A 가클래스 B 로생성되었으면 true 를반환 3. 동일한수퍼클래스에서상속된서브클래스의객체들을하나의타입으로취급할때유용하다 4. 수퍼클래스타입으로선언하는것이좋다 p 내부클래스는하나의클래스안에다른클래스를정의하는것으로클래스의모든멤버를참조할수있다. 2. 내부클래스는 private 로선언된필드도접근이가능하다. p new 키워드다음에수퍼클래스이름이나인터페이스이름을적어준다 2. 무명클래스를정의하면클래스정의와객체생성을동시에할수있다. 3. new Object()...

46 import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.timer; public class CallbackTest public static void main(string[] args) ActionListener listener = new MyClass(); Timer t = new Timer(1000, listener); t.start(); for (int i = 0; i < 1000; i++) try Thread.sleep(1000); catch (InterruptedException e) class MyClass implements public void actionperformed(actionevent e) // TODO Auto-generated method stub System.out.println("beep"); 1. class AudioSystem extends SoundSystem implements MP3playable, TurnTableplayable 인터페이스안에는추상메소드만정의할수있다. public interface MyInterface void MyMethod(int value);

47 3. abstract class Bird abstract public void sound(); class Dove extends Bird public void sound() System.out.println("coo coo"); 4. public interface Edible //boolean amount; 필드는정의할수없다. final int TYPE=10; public void eat(); // ; 추상메소드만정의할수있다. ; public class Sandwitch implements Edible public void eat() 5. (2) 6. (3) 7. a, b, c, d 9. (1) 수퍼클래스참조변수는서브클래스객체를가리킬수있다. (2) 가능하다. (3) 오타! 다음과같은문장은적법한가? 그이유는? Point3D p = new Point2D(); -> 적법하지않다. 수퍼클래스객체를서브클래스참조변수로가리킬수없다. (4) class Point2D public int getx() return x; public void setx(int x) this.x = x; public int gety() return y; public void sety(int y) this.y = y; private int x; private int y; class Point3D extends Point2D public int getz() return z;

48 public void setz(int z) this.z = z; private int z; 1. interface Movable void move(int dx, int dy); class Shape implements Movable protected int x, y; public void draw() System.out.println("Shape Draw"); ; public void move(int dx, int dy) x = dx; y = dy; class Rectangle extends Shape private int width, height; ; public void setwidth(int w) width = w; public void setheight(int h) height = h; public void draw() System.out.println("Rectangle Draw"); class Triangle extends Shape private int base, height;

49 public void draw() System.out.println("Triangle Draw"); public void move(int dx, int dy) x = dx; y = dy; class Circle extends Shape private int radius; ; public void draw() System.out.println("Circle Draw"); public class ShapeTest private static Movable arrayofshapes[]; public static void main(string arg[]) init(); moveall(); public static void init() arrayofshapes = new Shape[3]; arrayofshapes[0] = new Rectangle(); arrayofshapes[1] = new Triangle(); arrayofshapes[2] = new Circle(); ; public static void moveall() for (int i = 0; i < arrayofshapes.length; i++) arrayofshapes[i].move(10, 10); 2. 오타! 다음과같이수정하여주세요. 다음과같은인터페이스들을정의하라. public interface Drawable void draw(); 본문의 ShapeTest.java 에등장하는 2 차원도형인원, 사각형, 삼각형등이위의인터페이스를구현하도록수정하라. draw() 메소드에서는실제로그리지는않고메시지만을출력하라. main() 에서 Drawable 객체배열을생성하고배열의각원소에대하여 draw() 를호출하는프로그램을작성하라.

50 interface Drawable void draw(); class Shape implements Drawable protected int x, y; ; public void draw() System.out.println("Shape Draw"); class Rectangle extends Shape private int width, height; ; public void setwidth(int w) width = w; public void setheight(int h) height = h; public void draw() System.out.println("Rectangle Draw"); class Triangle extends Shape private int base, height; ; public void draw() System.out.println("Triangle Draw"); class Circle extends Shape private int radius; ; public void draw() System.out.println("Circle Draw"); public class ShapeTest private static Drawable arrayofshapes[]; public static void main(string arg[]) init(); drawall();

51 public static void init() arrayofshapes = new Shape[3]; arrayofshapes[0] = new Rectangle(); arrayofshapes[1] = new Triangle(); arrayofshapes[2] = new Circle(); ; public static void drawall() for (int i = 0; i < arrayofshapes.length; i++) arrayofshapes[i].draw(); 3. interface controllable void play(); void stop(); public class Test public static void main(string arg[]) controllable c = new controllable() public void play() System.out.println("PLAY"); public void stop() System.out.println("STOP"); ; ; c.play(); c.stop(); 4. interface Comparable // 이객체가다른객체보다크면 1, 같으면 0, 작으면 -1 을반환한다. int compareto(object other); class Person implements public String tostring() return "Person [name=" + name + ", height=" + height + "]"; public Person(String name, double height) super(); this.name = name; this.height = height; String name;

52 double public int compareto(object other) if ( this.height > ((Person)other).height ) return 1; else if ( this.height == ((Person)other).height ) return 0; else return -1; public class Test public static Person getmaximum(person[] array) Person max=array[0]; for(int i=1;i<array.length;i++) if( array[i].height > max.height ) max = array[i]; return max; public static void main(string arg[]) Person[] array; array = new Person[3]; array[0] = new Person(" 홍길동1", 190); array[1] = new Person(" 홍길동2", 180); array[2] = new Person(" 홍길동3", 185); System.out.println(getMaximum(array)); 5. 생략 6. 생략 p 컴포넌트

53 2. AWT 는운영체제에서제공하는컴포넌트를그대로사용한것이다. 스윙은자바가직접각컴포넌트를작성한것이다. 3. 스윙에서기본적으로제공된다. 4. setvisible() 메소드는 Window 클래스에서제공한다. 따라서 Window 를상속받는클래스들이사용할수있다. 예를들어서 JFrame 클래스가사용할수있다. p 다른컴포넌트들을내부에넣을수있는기능을가진다. 2. 절대다른컨테이너안에포함될수없는컨테이너로프레임, 다이알로그, 애플릿이있다. p 프레임객체생성 -> 버튼생성 -> 버튼을프레임에추가 2. class MyFrame extends JFrame public MyFrame()... JButton button1 = new JButton(" 버튼 1"); JButton button2 = new JButton(" 버튼 2"); this.add(button1); this.add(button2); p class MyFrame extends JFrame public MyFrame()... JLabel label = new JLabel(" 레이블 "); JButton button = new JButton(" 버튼 "); this.add(label); this.add(button); 2. 패널에버튼을추가하면버튼 3 개가나란히보이지만, 프레임에버튼 3 개를추가하면마지막버튼만프레임전체에보인다. 1. (1) JButton (2) 버튼, 레이블, 텍스트필드등 (3) JFrame 클래스를확장하여야한다. (4) 화면에표시되어서사용자와상호작용하는시각적인객체를나타내며 add(), getwidth(), getx(), setfont() 등이사용된다.

54 (5) 컨테이너생성 -> 컴포넌트생성 -> 컴포넌트를컨테이너에추가 2. (1) 거짓 - 패널은다른패널을포함할수있다. (2) 거짓 - 스윙의컴포넌트수가 AWT 보다많다. (3) 거짓 - add() (4) 거짓 - 프레임은최상위컨테이너라다른컨테이너안에포함될수없다. 3. (1) import javax.swing.*; (2) button = new JButton(" 동작 "); (3) JButton button1, button2; (4) JLabel label = new JLabel(); 4. (1) JLabel, JButton, JPanel, JFrame (2) setsize(500,100); (3) JPanel panel = new JPanel(); (4) JLabel label = new JLabel(" 자바는재미있나요?"); (5) JButton button1 = new JButton("Yes"); JButton button2 = new JButton("No"); (6) panel.add(label); panel.add(button1); panel.add(button2); (7) add(panel); 1. import java.awt.*; import javax.swing.*; class TestFrame extends JFrame public TestFrame() setsize(500,100); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 테스트프레임 "); JPanel panel = new JPanel(); JLabel label = new JLabel(" 자바는재미있나요?"); JButton button1 = new JButton("Yes"); JButton button2 = new JButton("No"); panel.add(label); panel.add(button1);

55 panel.add(button2); add(panel); setvisible(true); public class TestFrameT public static void main(string[] args) TestFrame f = new TestFrame(); 2. import java.awt.*; import javax.swing.*; class MyFrame extends JFrame public MyFrame() setsize(500,150); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 테스트프레임 "); JPanel panel1 = new JPanel(); JLabel label1 = new JLabel(" 인간에게주어진최사의선물은마음껏웃을수있다는것이다."); JLabel label2 = new JLabel(" 가능한목표라고하더라도그것을꿈꾸고상상하는순간이미거기에다가가있는것이다. "); JLabel label3 = new JLabel(" 상상력은생존의힘이다."); panel1.add(label1); panel1.add(label2); panel1.add(label3); add(panel1); setvisible(true); public class MyFrameTest public static void main(string[] args) MyFrame f = new MyFrame(); 3. import java.awt.*; import javax.swing.*; class MyFrame extends JFrame public MyFrame() setsize(400,150);

56 setdefaultcloseoperation(jframe.exit_on_close); settitle(" 테스트프레임 "); JPanel panel1 = new JPanel(); JPanel panel2 = new JPanel(); JPanel panel3 = new JPanel(); JLabel label1 = new JLabel(" 자바호텔에오신것을환영합니다."); JLabel label2 = new JLabel(" 숙박일수를입력하세요."); JButton button1 = new JButton("1명 "); JButton button2 = new JButton("2명 "); JButton button3 = new JButton("3명 "); JButton button4 = new JButton("4명 "); JButton button5 = new JButton("5명 "); panel1.add(label1); panel1.add(label2); panel2.add(button1); panel2.add(button2); panel2.add(button3); panel2.add(button4); panel2.add(button5); panel3.add(panel1); panel3.add(panel2); add(panel3); setvisible(true); public class MyFrameTest public static void main(string[] args) MyFrame f = new MyFrame();

57 import java.awt.flowlayout; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; class MyFrame extends JFrame JPanel p1; public MyFrame() setsize(300, 200); settitle("my Frame"); p1 = new JPanel(); p1.setlayout(new FlowLayout()); for (int i = 0; i < 10; i++) p1.add(new JButton("Button" + i)); add(p1); setvisible(true); // 프레임을화면에표시한다. public class MyFrameTest public static void main(string args[]) MyFrame f = new MyFrame(); 1. 마지막에추가한버튼이다른버튼들을전부가리게된다.

58 2. 3. GridLayout(1, 0) 4. import java.awt.color; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; class MyFrame extends JFrame JPanel p = new JPanel(); JLabel[] labels = new JLabel[30]; public MyFrame() p.setlayout(null); for (int i = 0; i < 30; i++) labels[i] = new JLabel("" + i); int x = (int) (500 * Math.random()); int y = (int) (200 * Math.random()); labels[i].setforeground(color.magenta); labels[i].setlocation(x, y); labels[i].setsize(20, 20); p.add(labels[i]); setsize(500, 300); add(p); setvisible(true); // 프레임을화면에표시한다. public class MyFrameTest public static void main(string args[]) MyFrame f = new MyFrame();

59 1. // 패키지포함 import java.awt.gridlayout; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.jtextfield; // JFrame 을상속받는 MyFrame 클래스선언 class MyFrame extends JFrame // 필드선언 private JButton button; private JLabel label; private JTextField textinput,textresult; private JPanel panel,panel1,panel2,panel3; // 생성자선언 public MyFrame() setsize(500,200); // 프레임의크기설정 setdefaultcloseoperation(jframe.exit_on_close); // 종료버튼을눌렀을때프레임이닫히도록설정 settitle(" 마일을킬로미터로변환 "); // 프레임의제목설정

60 panel = new JPanel(); // panel 에패널객체생성 panel.setlayout(new GridLayout(0, 1)); panel1 = new JPanel(); // panel 에패널객체생성 panel2 = new JPanel(); // panel 에패널객체생성 panel3 = new JPanel(); // panel 에패널객체생성 객체생성 label= new JLabel(" 거리를마일단위로입력하세요 "); // label 에레이블 textinput = new JTextField(10); // textinput에텍스트필드객체생성 panel1.add(label); // 패널에레이블추가 panel1.add(textinput); // 패널에텍스트필드추가 button = new JButton(" 변환 "); // button 에버튼객체생성 panel2.add(button); // 패널에버튼추가 드객체생성 textresult = new JTextField(30); // textresult 에크기가 30 인텍스트필 panel3.add(textresult); // 패널에텍스트필드추가 panel.add(panel1); panel.add(panel2); panel.add(panel3); add(panel); // 프레임에패널추가 setvisible(true); // 프레임출력메소드 public class MyFrameTest public static void main(string[] args) MyFrame f = new MyFrame(); // 객체생성 2. import java.awt.gridlayout; import java.awt.event.*; import javax.swing.*;

61 class Myframe extends JFrame JButton button; JTextField t1; JTextField t2; JTextField t3; private JPanel panel,panel1,panel2,panel3, panel4; public Myframe() setsize(230,150); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 이자계산기 "); JPanel panel=new JPanel(new GridLayout(0, 1)); JPanel panel1=new JPanel(); JPanel panel2=new JPanel(); JPanel panel3=new JPanel(); JPanel panel4=new JPanel(); JLabel label1=new JLabel(" 원금을입력하시오 "); t1=new JTextField(5); panel1.add(label1); panel1.add(t1); JLabel label2=new JLabel(" 이율을입력하시오 "); t2=new JTextField(5); panel2.add(label2); panel2.add(t2); button=new JButton(" 변환 "); panel3.add(button); t3=new JTextField(20); panel4.add(t3); panel.add(panel1); panel.add(panel2); panel.add(panel3); panel.add(panel4); this.add(panel); setvisible(true); public class MyFrameTest public static void main(string[] arge) Myframe f=new Myframe();

62 3. 오타! 문제의그림을다음과같이수정하여주세요. 윈도우제목 계산기 23 텍스트필드 C / * 버튼 /- = + import java.awt.flowlayout; import java.awt.gridlayout; import javax.swing.boxlayout; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jtextfield; class MyFrame extends JFrame public MyFrame() JPanel p, p1, p2, p3; JTextField tf; JButton[] b = new JButton[17]; p = new JPanel(); p.setlayout(new BoxLayout(p, BoxLayout.Y_AXIS)); p1 = new JPanel(); FlowLayout layout = new FlowLayout(); layout.setalignment(flowlayout.left); layout.setvgap(0); p1.setlayout(layout); p2 = new JPanel(); p2.setlayout(layout);

63 p3 = new JPanel(new GridLayout(0, 4)); tf = new JTextField(30); p1.add(tf); b[0] = new JButton("C"); b[1] = new JButton("7"); b[2] = new JButton("8"); b[3] = new JButton("9"); b[4] = new JButton("/"); b[5] = new JButton("4"); b[6] = new JButton("5"); b[7] = new JButton("6"); b[8] = new JButton("*"); b[9] = new JButton("1"); b[10] = new JButton("2"); b[11] = new JButton("3"); b[12] = new JButton("-"); b[13] = new JButton("0"); b[14] = new JButton("+/-"); b[15] = new JButton("="); b[16] = new JButton("+"); p2.add(b[0]); for (int i=1; i<17; i++) p3.add(b[i]); p.add(p1); p.add(p2); p.add(p3); add(p); setdefaultcloseoperation(jframe.exit_on_close); pack(); setvisible(true); public class MyFrameTest public static void main(string[] args) new MyFrame();

64 p 오류 : 아직이벤트처리를학습하지않았는데문제가이벤트처리를요구하고있습니다. 다음과같이문제를변경하여주십시오. SnowManFace 에서찡그린얼굴을그리도록소스를수정하라. import java.awt.borderlayout; import java.awt.color; import java.awt.graphics; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; class MyPanel extends JPanel int type = 0; public void paintcomponent(graphics g) super.paintcomponent(g); if( type == 0 ) g.setcolor(color.yellow); g.filloval(20, 30, 200, 200); g.setcolor(color.black);

65 else g.drawarc(60, 80, 50, 50, 180, -180); // 왼쪽눈 g.drawarc(150, 80, 50, 50, 180, -180); // 오른쪽눈 g.drawarc(70, 130, 100, 70, 180, 180); // 입 g.setcolor(color.yellow); g.filloval(20, 30, 200, 200); g.setcolor(color.black); g.drawarc(60, 80, 50, 50, 180, +180); // 왼쪽눈 g.drawarc(150, 80, 50, 50, 180, +180); // 오른쪽눈 g.drawarc(70, 130, 100, 70, 180, 180); // 입 public int gettype() return type; public void settype(int type) this.type = type; repaint(); public class SnowManFace extends JFrame implements ActionListener MyPanel panel; public SnowManFace() setsize(280, 300); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 눈사람얼굴 "); setvisible(true); panel = new MyPanel(); add(panel); JButton b = new JButton(" 찡그린얼굴 "); add(b, BorderLayout.SOUTH); b.addactionlistener(this); public static void main(string[] args) SnowManFace s = new public void actionperformed(actionevent arg0) panel.settype(1);

66 2. 생략 p mylabel.setfont(new Font("Dialog", Font.ITALIC, 10)); 1. import java.awt.graphics; import javax.swing.jcomponent; import javax.swing.jframe; class MyComponent extends JComponent // JComponent 를상속받은 MyComponent 클래스생성 public void paint(graphics g) // paint 메소드재정의 g.drawline(10, 80, 100, 10); // x, y좌표 10, 80부터 100, 10까지선긋기 g.drawstring("drawline()", 10, 100); // x, y 좌표 10, 100 에문자열그리기 g.drawrect(110, 10, 110, 80); // x, y 좌표 10, 80 부터 100, 10 까지사각형그리기 g.drawstring("drawrect()", 110, 100); // x, y 좌표 10, 100 에문자열그리기 // public class Test public static void main(string[] args)

67 JFrame frame = new JFrame(); // JFrame 객체생성 frame.setsize(800, 300); // 프레임사이즈 frame.settitle(" 그리기 "); // 프레임제목 frame.setdefaultcloseoperation(jframe.exit_on_close); MyComponent component = new MyComponent(); // MyComponent 객체생성 frame.add(component); frame.setvisible(true); // Component를프레임에추가 // 프레임을보이게함 위의소스를분석하고주석을달아라. 번위치에나머지도형들을그리는문장들을추가하라. - 도형들을그리는 draw메소드를호출해서도형을생성하고그밑에 drawstring메소드를사용해어떤도형인지를문자열로나타내준다. 각도형마다 Graphics객체를통하여메소드를호출한다. 각도형마다매개변수로보내줘야할변수들이다르기때문에각메소드를충분히숙지하고사용해야한다. 도형을그리는색상을변경하여보자. 예를들어서사각형의색상을빨간색으로변경하여보라. - g.setcolor(color.red); 이처럼역시객체 g를통해색에관한설정자를불러색을바꿔준다. 텍스트 "drawrect()" 의폰트를 "Serif", 12포인트, 볼드체로변경하여보자. - g.setfont(new Font("Serif", Font.BOLD, 12)); 이처럼 Font설정자를불러텍스트를형태를바꿔준다. drawarc() 의각도를변경하여보자. - 설정자를통해각도를설정하는방법도있지만밑소스에서는도형을초기화할때각도를다르게해주었다. import java.awt.*; import javax.swing.*; class MyComponentextends JComponent public void paint(graphics g) setforeground(color.gray); //3D 효과를돋보이게하기위해색을 gray 로바꾸어줌 setbackground(color.gray); // 도형을그리고문자열출력을반복 g.setcolor(color.red); // 색깔을바꿔주는설정자호출, 빨간색으로선색을바꿈 g.drawline(10, 80, 100, 10); // 선 g.drawstring("drawline()", 10, 100); // 문자열출력 g.drawrect(110, 10, 110, 80); // 사각형 g.setfont(new Font("Serif", Font.BOLD, 12)); // 글자체변경 g.drawstring("drawrect()", 110, 100); g.setfont(new Font("sansSerif", Font.PLAIN, 12)); // 글자체변경 g.draw3drect(230, 10, 110, 80, true); //3D 사각형 g.drawstring("draw3drect()", 230, 100); g.setcolor(color.blue); // 파란색으로색을채워줌 g.drawroundrect(350, 10, 110, 80, 20, 20); // 둥근모서리사각형

68 g.drawstring("drawroundrect()", 350, 100); g.drawoval(470, 10, 110, 80); // 타원 g.drawstring("drawoval()", 470, 100); g.drawarc(590, 10, 110, 80, 80, 230); // 아크도형 g.drawstring("drawarc()", 590, 100); g.setcolor(color.green); // 초록색으로색을바꿔줌 int[] xpoints = 720, 830, 720, 830; //x 좌표배열생성 int[] ypoints = 10, 10, 90, 90; //y 좌표배열생성 int npoints = 4; // 점의개수 g.drawpolygon(xpoints, ypoints, npoints); //x, y 좌표를이용해 npoints 만큼점을만든다음선을이어줌 g.drawstring("drawpolygon()", 720, 100); g.fillrect(110, 120, 110, 80); // 색이채워진사각형 g.drawstring("drawrect()", 110, 210); g.setcolor(color.orange); // 오렌지색으로바꿈 g.fill3drect(230, 120, 110, 80, true); // 색이채워진 3D 사각형 g.drawstring("draw3drect()", 230, 210); g.fillroundrect(350, 120, 110, 80, 20, 20); // 색이채워진둥근모서리사각형 g.drawstring("drawroundrect()", 350, 210); g.setcolor(color.pink); g.filloval(470, 120, 110, 80); // 색이채워진타원 g.drawstring("drawoval()", 470, 210); g.fillarc(590, 120, 110, 80, 90, 120); // 색이채워진아크도형 g.drawstring("drawarc()", 590, 210); int[] x = 720, 830, 720, 830; int[] y = 120, 120, 200, 200; int n = 4; g.fillpolygon(x, y, n); // 색이채워진폴리건 g.drawstring("fillpolygon()", 720, 210); public class Test public static void main(string[] args) JFrame frame = new JFrame(); // JFrame 객체생성 frame.setsize(900, 300); // 프레임사이즈 frame.settitle(" 그리기 "); // 프레임제목 frame.setdefaultcloseoperation(jframe.exit_on_close); MyComponent component = new MyComponent(); // MyComponent 객체생성 frame.add(component); frame.setvisible(true); // Component를프레임에추가 // 프레임을보이게함

69 2. 생략 ( 책의본문에있는프로그램과유사 ) 3. import java.awt.*; import javax.swing.*; class MyComponent extends JComponent //JComponent를상속받은 MyComponent public void paint(graphics g) //paint메소드재정의 int x=10; //x좌표초기화 int w1=110; // 타원의가로, 즉지름 for(int i=2 ; i<7 ; i++) g.drawoval(x, 10, w1, 80); // 타원을그려줌 g.drawstring("r = "+w1/2, x+w1/2, 50); // 타원안에반지름길이표시 x+=w1+20; w1+=i; // 타원하나를그릴때마다다음타원은지금의타원과 20 만큼거리를둠 // 가로의길이를늘려줌 // 정렬된모습을보여주기위해 5 개의타원은위에그리고나머지타원은아래에그려줌 x=10; //x 좌표를다시초기화 for(int i=2 ; i<7 ; i++) g.drawoval(x, 120, w1, 80); // 타원을그려줌 g.drawstring("r = "+w1/2, x+w1/2, 160); // 타원안에반지름길이표시

70 x+=w1+20; // 타원하나를그릴때마다다음타원은지금의타원과 20 만큼거리를둠 w1-=i; // 가로의길이를줄여줌 public class Test public static void main(string[] args) JFrame frame = new JFrame(); frame.setsize(750, 250); frame.settitle(" 그리기 "); frame.setdefaultcloseoperation(jframe.exit_on_close); MyComponent component = new MyComponent(); frame.add(component); frame.setvisible(true); 4. ( 생략 ) 1. 다음질문에간단히답하라. (1) java.awt (2) Color (3) Font (4) (0, 0) (5) 픽셀 (6) Graphics 2. 아래문장의참, 거짓을판단하고거짓이면그이유를말하라. (1) 거짓 - 위에서아래쪽으로증가한다. (2) 참 (3) 참 (4) 거짓 - 0 부터 255 까지 (5) 거짓 - 감싸는사각형의좌측상단의좌표이다.

71 3. 다음에서잘못된것을고쳐라. 다음코드에서 g 는 Graphics 객체를나타낸다. (1) g.setfont(new Font("Serif", Font.PLAIN, 10)); (2) g.setcolor(color.white); (3) Font f = new Font("Serif", Font.BOLD Font.ITALIC, 12); (4) Graphics 객체는사용자가생성할수없다. (5) g.setcolor(new Color(255, 0, 255)); 4. 자바에서색상은어떻게표현되는가? 빛의 3 원색인 Red 성분, Green 성분, Blue 성분이얼마나함유되어있는지를 0 에서 255 까지의수를사용하여나타낸다. 예를들어흰색은 (255, 255, 255) 가되고검정색은 (0, 0, 0), 노란색은 (255, 255, 0) 으로표현된다. 5. 자바에서다각형을표현하는 2 가지방법은무엇인가? 자바에서다각형은 Polygon 객체를이용하여서다각형을표현할수있다. (1) 다각형을배열을이용하여표현하고 Polygon 생성자를호출한다. Polygon(int[] xpoints, int[] ypoints, int npoints) 와같은생성자를사용한다. (2) Polygon() 을호출하여서비어있는 Polygon 객체를먼저생성하고나중에다각형의정점들을추가하여도된다. Polygon p = new Polygon(); p.addpoint(10, 10); 1. import javax.swing.*; import java.awt.event.*; import java.awt.*; class MyPanel extends JPanel Font f1, f2, f3, f4, f5; public MyPanel() f1 = new Font("Serif", Font.PLAIN, 20); f2 = new Font("San Serif", Font.BOLD, 20); f3 = new Font("Monospaced", Font.ITALIC, 20); f4 = new Font("Dialog", Font.BOLD Font.ITALIC, 20); f5 = new Font("DialogInput", Font.BOLD, 20); public void paintcomponent(graphics g) super.paintcomponent(g); for(int i=0; i< 10; i++) g.setfont(f1); Color color = new Color((int) (Math.random() * 255.0),

72 (int) (Math.random() * 255.0), (int) (Math.random() * 255.0)); g.setcolor(color); g.drawstring("hello World!", 10, 50+i*20); public class FontTest extends JFrame public FontTest() setsize(300, 400); setdefaultcloseoperation(jframe.exit_on_close); settitle("font Test"); JPanel panel = new MyPanel(); add(panel); setvisible(true); public static void main(string[] args) FontTest s = new FontTest(); 2. import javax.swing.*; import java.awt.event.*; import java.awt.*; class MyPanel extends JPanel Font[] fonts = new Font[5]; public MyPanel() fonts[0] = new Font("Serif", Font.PLAIN, 20); fonts[1] = new Font("San Serif", Font.BOLD, 20); fonts[2] = new Font("Monospaced", Font.ITALIC, 20); fonts[3] = new Font("Dialog", Font.BOLD Font.ITALIC, 20); fonts[4] = new Font("DialogInput", Font.BOLD, 20); public void paintcomponent(graphics g) super.paintcomponent(g); for(int i=0; i< 10; i++)

73 g.setfont(fonts[(int)(math.random()* )]); g.drawstring("hello World!", 10, 50+i*20); public class FontTest extends JFrame public FontTest() setsize(300, 400); setdefaultcloseoperation(jframe.exit_on_close); settitle("font Test"); JPanel panel = new MyPanel(); add(panel); setvisible(true); public static void main(string[] args) FontTest s = new FontTest(); 3. 생략 (Lab 문제와유사 ) 4. import java.awt.*; import java.awt.geom.*; import java.util.*; import javax.swing.*; class House extends JPanel public House() public void paintcomponent(graphics g) super.paintcomponent(g); Graphics2D g2=(graphics2d) g; g2.setstroke(new BasicStroke(3)); g2.setcolor(color.black); g2.draw(new Rectangle2D.Float(50,50,200,200)); g2.draw(new Rectangle2D.Float(150,150,50,100));

74 g2.draw(new Rectangle2D.Float(75,75,20,20)); g2.draw(new Line2D.Float(150, 20, 50, 50)); g2.draw(new Line2D.Float(150, 20, 250, 50)); class MyFrame extends JFrame public MyFrame() setsize(300,300); settitle("myframe"); setdefaultcloseoperation(jframe.exit_on_close); House H=new House(); H.setBounds(0, 0, 300, 300); add(h); setvisible(true); public class Test public static void main(string[] arge) MyFrame F=new MyFrame(); 5. import java.awt.*; import javax.swing.*; class BusinessCard extends JPanel public BusinessCard() public void paintcomponent(graphics g) super.paintcomponent(g); g.drawstring(" 홍길동 ", 150, 40); g.drawstring(" 프로젝트매니저 ", 150, 60); g.drawstring(" 자바주식회사 ", 150, 80); g.setcolor(color.red); g.filloval(20, 20, 80, 80);

75 class MyFrame extends JFrame public MyFrame() setsize(300,150); settitle("myframe"); setdefaultcloseoperation(jframe.exit_on_close); add(new BusinessCard()); setvisible(true); public class Test public static void main(string[] arge) MyFrame F=new MyFrame(); 6. import javax.swing.*; import java.awt.event.*; import java.awt.*; import java.awt.geom.*; class MyPanel extends JPanel public MyPanel() super(); setbackground( Color.yellow ); setsize( 400, 400 ); public void paintcomponent( Graphics g ) super.paintcomponent(g); int xpoints[] = 55, 67, 109, 73, 83, 55, 27, 37, 1, 43 ; int ypoints[] = 0, 36, 36, 54, 96, 72, 96, 54, 36, 36 ; Graphics2D g2d = ( Graphics2D ) g; GeneralPath star = new GeneralPath(); star.moveto( xpoints[ 0 ], ypoints[ 0 ] ); for ( int k = 1; k < xpoints.length; k++ )

76 star.closepath(); star.lineto( xpoints[ k ], ypoints[ k ] ); g2d.translate( 100, 100 ); for ( int j = 1; j <= 5; j++ ) g2d.rotate( Math.PI / 30.0 ); g2d.setcolor(new Color( ( int ) ( Math.random() * 256 ),( int ) ( Math.random() * 256 ), ( int ) ( Math.random() * 256 ) ) ); g2d.fill( star ); // draw a filled star public class MyFrame extends JFrame public MyFrame() setsize(300,300); settitle("myframe"); setdefaultcloseoperation(jframe.exit_on_close); add(new MyPanel()); setvisible(true); public static void main(string[] arge) MyFrame F=new MyFrame(); 7. /* SkyscraperApplet.java */ import java.awt.*; import javax.swing.jframe; import javax.swing.jpanel; class Skyscraper public int x; public int y; public int width; public int height;

77 Skyscraper(int x, int y, int w, int h) this.x = x; this.y = y; this.width = w; this.height = h; 255.0)); void draw(graphics g) Color color = new Color((int) (Math.random() * 255.0), (int) (Math.random() * 255.0), (int) (Math.random() * g.setcolor(color); g.fillrect(x, y, width, height); class MyPanel extends JPanel Skyscraper[] s = new Skyscraper[10]; public MyPanel() super(); for (int i = 0; i < 10; i++) s[i] = new Skyscraper((int) (Math.random() * 500), (int) (Math.random() * 300), (int) (Math.random() * 500), (int) (Math.random() * 300)); public void paintcomponent(graphics g) super.paintcomponent(g); for (int i = 0; i < 10; i++) s[i].draw(g); public class MyFrame extends JFrame public MyFrame() setsize(500, 300); settitle("myframe"); setdefaultcloseoperation(jframe.exit_on_close); add(new MyPanel()); setvisible(true); public static void main(string[] arge) MyFrame F = new MyFrame();

78 8. 생략 ( 앞의문제와유사함 ) 9. 이벤트처리는아직학습하지않았지만문제를흥미롭게하기위하여추가하였다. import java.awt.*; import java.awt.event.*; import java.applet.*; import javax.swing.jframe; import javax.swing.jpanel; class DoubleDice extends JPanel implements MouseListener int die1 = 4; int die2 = 3; public DoubleDice() super(); addmouselistener(this); setbackground(new Color(200, 200, 255)); public void paintcomponent(graphics g) drawdie(g, die1, 10, 10); drawdie(g, die2, 55, 55); void drawdie(graphics g, int val, int x, int y) g.setcolor(color.white); g.fillrect(x, y, 35, 35); g.setcolor(color.black); g.drawrect(x, y, 34, 34); if (val > 1) g.filloval(x + 3, y + 3, 9, 9); if (val > 3) g.filloval(x + 23, y + 3, 9, 9); if (val == 6) g.filloval(x + 3, y + 13, 9, 9); if (val % 2 == 1) g.filloval(x + 13, y + 13, 9, 9); if (val == 6) g.filloval(x + 23, y + 13, 9, 9); if (val > 3) g.filloval(x + 3, y + 23, 9, 9); if (val > 1)

79 g.filloval(x + 23, y + 23, 9, 9); void roll() die1 = (int) (Math.random() * 6) + 1; die2 = (int) (Math.random() * 6) + 1; repaint(); public void mousepressed(mouseevent evt) roll(); public void mousereleased(mouseevent evt) public void mouseclicked(mouseevent evt) public void mouseentered(mouseevent evt) public void mouseexited(mouseevent evt) public class MyFrame extends JFrame public MyFrame() setsize(100, 180); settitle("myframe"); setdefaultcloseoperation(jframe.exit_on_close); add(new DoubleDice()); setvisible(true); public static void main(string[] arge) MyFrame F = new MyFrame(); 10. // awt 와 swing 패키지포함 import java.awt.*;

80 import javax.swing.*; // JComponent 를상속받는 Mycomponent 클래스선언 class Car extends JComponent // 자동차의색상과위치 ( 좌표 ), 크기를받을필드선언 private String color; private int size1; private int size2; private int location1; private int location2; // 각필드를매개변수로받는생성자선언 public Car(String color, int location1, int location2, int size1, int size2) this.color = color; this.size1 = size1; this.size2 = size2; this.location1 = location1; this.location2 = location2; // paint() 메소드를재정의하여자동차의그림을그림 public void paint(graphics g) // 자동차차체의색상설정 g.setcolor(color.green); // fillrect() 메소드를사용하여사용자로부터입력받은좌표와크기로몸체 ( 사각형 ) 를그림 g.fillrect(location1, location2, size1, size2); // 창문의색상설정 g.setcolor(color.white); /* fillrect() 메소드를사용하여사용자로부터입력받은좌표를수정해몸체안에폭 30, 너비 30의창문 ( 사각형 ) 을 2개만듬 */ g.fillrect(location1+10, location2+10, 30, 30); g.fillrect(location1+50, location2+10, 30, 30); // 자동차바퀴의색상설정 g.setcolor(color.black); /* filloval() 메소드를사용하여사용자로부터입력받은좌표를수정해폭 25, 너비 25의바퀴 ( 원 ) 을 2개만듬 */ g.filloval(location1, location2+size2, 25, 25); g.filloval(location1+size1-25, location2+size2, 25, 25); public class Test // Test 클래 스선언 public static void main(string args[]) // 메인메소드선언 // Jframe 타입의참조변수 frame을선언해객체를가르키도록함 JFrame frame = new JFrame(); frame.setsize(1200, 500); // 프레임의사이즈설정 frame.settitle(" 그리기 "); // 타이틀을 " 그리기 " 로설정 // 컴포넌트를격자모양으로배치하는배치관리자 GridLayout 설정 frame.setlayout(new GridLayout()); // x버튼을누를시프로그램이종료되도록설정 frame.setdefaultcloseoperation(jframe.exit_on_close);

81 생성생성생성생성 Car car1 = new Car("blue", 10, 10, 200, 100); Car car2 = new Car("red", 10, 300, 150, 80); Car car3 = new Car("green", 5, 150, 250, 150); Car car4 = new Car("black", 100, 200, 100, 70); // car 객체들을프레임에포함 frame.add(car1); frame.add(car2); frame.add(car3); frame.add(car4); // 첫번째 car 객체 // 두번째 car 객체 // 세번째 car 객체 // 네번째 car 객체 // 프레임을화면에보이도록시각화함 frame.setvisible(true); 11. 이벤트처리는아직학습하지않았지만문제를흥미롭게하기위하여추가하였다. import java.awt.borderlayout; import java.awt.color; import java.awt.graphics; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; class MyPanel extends JPanel implements ActionListener boolean flag = false; private int light_number = 0; public MyPanel() setlayout(new BorderLayout()); JButton b = new JButton(" 신호변경 "); b.addactionlistener(this); add(b,

82 protected void paintcomponent(graphics g) // TODO Auto-generated method stub super.paintcomponent(g); g.setcolor(color.black); g.drawoval(100, 100, 100, 100); g.drawoval(100, 200, 100, 100); g.drawoval(100, 300, 100, 100); if (light_number == 0) g.setcolor(color.red); g.filloval(100, 100, 100, 100); else if (light_number == 1) g.setcolor(color.green); g.filloval(100, 200, 100, 100); else g.setcolor(color.yellow); g.filloval(100, 300, 100, public void actionperformed(actionevent arg0) // TODO Auto-generated method stub if (++light_number >= 3) light_number = 0; repaint(); public class MyFrame extends JFrame public MyFrame() add(new MyPanel()); setsize(300, 500); setvisible(true); public static void main(string[] arg) new MyFrame();

83 12. ( 생략 )

84 p 이벤트가발생한다. 2. 이벤트처리기 3. 내부클래스는외부클래스의멤버에접근할수있다. 1. import java.awt.font; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; class MyCounter extends JFrame implements ActionListener private JLabel label, label1; private JButton button1, button2; private int count = 0; public MyCounter() JPanel panel = new JPanel(); label = new JLabel("Counter"); panel.add(label); label1 = new JLabel("" + count); label1.setfont(new Font("Serif", // 레이블에폰트를설정한다. Font.BOLD Font.ITALIC, 100)); panel.add(label1);

85 button1 = new JButton(" 카운터증가 "); panel.add(button1); button1.addactionlistener(this); button2 = new JButton(" 카운터감소 "); panel.add(button2); button2.addactionlistener(this); add(panel); setsize(400, 200); settitle("my Counter"); public void actionperformed(actionevent event) if( event.getsource() == button1 ) count++; label1.settext(count + ""); else count--; label1.settext(count + ""); public class CounterTest public static void main(string[] args) new MyCounter(); 2. 도전과제중에서 1 번만을구현하였습니다. import java.awt.font; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; class MyCounter extends JFrame implements ActionListener private JLabel[] labels;

86 private JLabel score; private JButton button; private int[] numbers; public MyCounter() setsize(500, 300); JPanel panel = new JPanel(); panel.setlayout(null); labels = new JLabel[3]; score = new JLabel("000"); numbers = new int[3]; 100)); for (int i = 0; i < 3; i++) labels[i] = new JLabel("" + numbers[i]); labels[i].setfont(new Font("Serif", Font.BOLD Font.ITALIC, labels[i].setsize(100, 100); labels[i].setlocation( * i, 20); panel.add(labels[i]); button = new JButton(" 스핀 "); button.setsize(250, 50); button.setlocation(100, 150); panel.add(button); score.setfont(new Font("Serif", Font.BOLD Font.ITALIC, 30)); score.setsize(250, 50); score.setlocation(100, 200); panel.add(score); button.addactionlistener(this); add(panel); settitle("my Game"); public void actionperformed(actionevent event) for (int i = 0; i < 3; i++) numbers[i] = (int) (Math.random() * 10); labels[i].settext("" + numbers[i]); if( labels[0].gettext().equals(labels[1].gettext()) && labels[0].gettext().equals(labels[2].gettext()) ) score.settext("100"); else score.settext("000");

87 public class CounterTest2 public static void main(string[] args) new MyCounter(); 1. (1) 참 (2) 참 (3) 거짓 - 마우스가움직였을때발생하는이벤트는 MouseMotionEvent 이다 (4) 거짓 - 어댑터클래스를사용하면원하는메소드만을구현하는것이가능해짐 (5) 거짓 - getkeychar() 는문자를반환한다. getkeycode() 를사용해야시프트키를검출할수있다. 2. JButton b = new JButton("test"); b.addactionlistener(new MyListener()); 3. keypressed() -> keytyped() -> KeyReleased() 4. this.addmouselistener(new MouseAdapter() public void mousepressed(mouseevent e) img_x = e.getx(); img_y = e.gety(); repaint(); ); 5. class MyFrame extends JFrame JButton button; public MyFrame() button = new JButton(" 버튼을누르시오 "); button.addactionlistener(new ActionListener() public void actionperformed(actionevent e) System.out.println(" 마침내버튼이눌려졌습니다."); ); 6. class MyFrame extends JFrame JButton button; public MyFrame() button = new JButton(" 버튼을누르시오 ");

88 button.addactionlistener(new MyListener()); private class MyListener implements public void actionperformed(actionevent arg0) System.out.println(" 마침내버튼이눌려졌습니다."); 1. import java.awt.event.*; import javax.swing.*; class Myframe extends JFrame JButton button; JTextField t1; JTextField t2; public Myframe() setsize(250,120); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 마일을킬로미터로변환 "); JPanel panel1=new JPanel(); JLabel label=new JLabel(" 거리를마일단위로입력하시오 "); t1=new JTextField(5); t2=new JTextField(20); button=new JButton(" 변환 "); button.addactionlistener(new MyListener()); t1.settext("1"); t2.seteditable(false); panel1.add(label); panel1.add(t1); panel1.add(button); panel1.add(t2); this.add(panel1); setvisible(true); private class MyListener implements ActionListener public void actionperformed(actionevent e)

89 if(e.getsource()==button) int t=integer.parseint(t1.gettext()); double k=t* ; t2.settext(t+" 마일은 "+k+" 킬로미터입니다."); public class Pro1 public static void main(string[] arge) Myframe f=new Myframe(); 2. import java.awt.event.*; import javax.swing.*; class Myframe extends JFrame JButton button; JTextField t1; JTextField t2; JTextField t3; public Myframe() setsize(230,150); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 이자계산기 "); JPanel panel1=new JPanel(); JLabel label1=new JLabel(" 원금을입력하시오 "); JLabel label2=new JLabel(" 이율을입력하시오 "); t1=new JTextField(5); t2=new JTextField(5); t3=new JTextField(15); button=new JButton(" 변환 "); button.addactionlistener(new MyListener()); t3.seteditable(false); panel1.add(label1); panel1.add(t1); panel1.add(label2); panel1.add(t2);

90 panel1.add(button); panel1.add(t3); this.add(panel1); setvisible(true); private class MyListener implements ActionListener public void actionperformed(actionevent e) if(e.getsource()==button) int t=integer.parseint(t1.gettext()); float a=float.parsefloat(t2.gettext()); int k=(int)(t*(a/100)); t3.settext(" 이자는연 "+k+" 만원입니다."); public class Pro2 public static void main(string[] arge) Myframe f=new Myframe(); // 이항연산을표현하는클래스 public class DyadicOperation private double operandx; private double operandy; private char operator; // 생성자 public DyadicOperation() init(); // 초기화 public void init() setoperandx(0); setoperandy(0);

91 setoperator('='); // 접근자 public double getoperandx() return operandx; public double getoperandy() return operandy; public char getoperator() return operator; // 설정자 public void setoperandx(double operandx) this.operandx = operandx; public void setoperandy(double operandy) this.operandy = operandy; public void setoperator(char operator) this.operator = operator; // 식입력 ( 피연산자일때 ) public void inputfomula(double operand) if(operator == '=') setoperandx(operand); setoperandy(operand); else setoperandy(operand); // 식입력 ( 연산자일때 ) public boolean inputfomula(char operator) if(operator!= '=' && operator!= '%') if(getoperator()!= '=') calculate(); setoperator(operator); return true; else setoperator(operator); return false; else if(operator == '=' && getoperator()!= '=') calculate(); return true; else if(operator == '%' && getoperator() == '*') setoperandx(getoperandx()*getoperandy()*0.01); return true; return false; // 연산 public void calculate() switch(getoperator()) case '+': setoperandx(getoperandx() + getoperandy()); break;

92 case '-': setoperandx(getoperandx() - getoperandy()); break; case '*': setoperandx(getoperandx() * getoperandy()); break; case '/': setoperandx(getoperandx() / getoperandy()); break; import java.awt.borderlayout; import java.awt.color; import java.awt.flowlayout; import java.awt.gridlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.jtextfield; // 계산기를구현하는클래스 public class MyCalculator extends JFrame private JTextField f;// 텍스트필드 private boolean resultprint;// 결과출력상태 private DyadicOperation operation;// 이항연산클래스 private Real num;// 실수 // 생성자 public MyCalculator() // 슈퍼클래스생성자명시적호출을통한프레임제목설정 super("mycalculator"); f = new JTextField("0.");// 텍스트필드 setresultprint(false);// 결과출력상태 operation = new DyadicOperation();// 이항연산클래스 num = new Real();// 실수 border 선택 // 메인패널로사용할패널을생성 JPanel mainpanel = new JPanel(); //flow, border, grid 중텍스트필드와키패널의비대칭적크기를고려해 mainpanel.setlayout(new BorderLayout(10,10)); // 텍스트필드생성및추가 f.sethorizontalalignment(jtextfield.right); f.seteditable(false); f.setbackground(color.white); mainpanel.add(f,borderlayout.north);

93 는 flow 선택 // 키패널생성및추가 JPanel mainkeypanel = new JPanel(); mainkeypanel.setlayout(new BorderLayout(10,10)); KeyPanel1 keypanel1 = new KeyPanel1(); KeyPanel2 keypanel2 = new KeyPanel2(); mainkeypanel.add(keypanel1,borderlayout.north); mainkeypanel.add(keypanel2,borderlayout.center); mainpanel.add(mainkeypanel,borderlayout.center); // 메인패널을프레임에추가 add(mainpanel); //flow, border, grid 중프레임과메인패널사이에적절한공간을줄수있 setlayout(new FlowLayout(FlowLayout.CENTER, 10, 10)); setdefaultcloseoperation(jframe.exit_on_close); pack(); setresizable(false); setvisible(true); // 키패널클래스 1 class KeyPanel1extends JPanel public KeyPanel1() //flow, border, grid 중버튼정렬을하기가장적합한 grid 선택 setlayout(new GridLayout(0,3,10,10)); String[] str = new String[] "Backspace", "CE", "C"; JButton[] button = new JButton[str.length]; //Backspace, CE, C의순서로버튼이추가되도록반복 for(int i=0; i<str.length; i++) button[i] = new JButton(str[i]); button[i].setbackground(color.white); button[i].setforeground(color.red); add(button[i]); button[i].addactionlistener(new MyActionListener1()); // 액션리스너 1 클래스 class MyActionListener1 implements ActionListener// public void actionperformed(actionevent e) if(e.getactioncommand()=="c")// 초기화 operation.init(); num.init(); else if(e.getactioncommand()=="ce")// 현재입력한값초기화 num.init(); else//backspace num.backspace();

94 f.settext(num.tostring()); // 키패널클래스 2 class KeyPanel2extends JPanel// 내부클래스 public KeyPanel2()// 생성자 //flow, border, grid 중버튼정렬을하기가장적합한 grid 선택 setlayout(new GridLayout(0,5,10,10)); String[] str = new String[] "7", "8", "9", "/", "sqrt", "4", "5", "6", "*", "%", "1", "2", "3", "-", "1/x", "0", "+/-", ".", "+", "="; JButton[] button = new JButton[str.length]; //7, 8, 9, /, sqrt,4,5,6,*,%,1,2,3,-, //1/x, 0, +/-,., +, = 의순서로버튼이추가되도록반복 for(int i=0; i<str.length; i++) button[i] = new JButton(str[i]); add(button[i]); button[i].setbackground(color.white); button[i].addactionlistener(new MyActionListener2()); button[3].setforeground(color.red); button[8].setforeground(color.red); button[13].setforeground(color.red); button[18].setforeground(color.red); button[19].setforeground(color.red); // 액션리스너 2 클래스 class MyActionListener2 implements public void actionperformed(actionevent e) // 내부클래스 // TODO Auto-generated method stub String str = e.getactioncommand(); if(str.length() == 1)// 단문자인경우 switch(str.charat(0)) // 이항연산자인경우 case '/': case '*': case '-': case '+': case '=': case '%': if(num.tostring()!= "0.") operation.inputfomula(double.parsedouble(num.tostring())); setresultprint(operation.inputfomula(str.charat(0))); if(isresultprint()) num.setreal(operation.getoperandx()); f.settext(num.tostring());

95 else num.init(); break; default: num.inputappend(str.charat(0)); f.settext(num.tostring()); break; if(str == "+/-") num.sign(); else if(str == "1/x") num.inverse(); else num.sqrt(); f.settext(num.tostring()); // 접근자 public boolean isresultprint() return resultprint; // 설정자 public void setresultprint(boolean resultprint) this.resultprint = resultprint; public static void main(string[] args) MyCalculator c=new MyCalculator(); 4. import java.awt.borderlayout; import java.awt.color; import java.awt.graphics; import java.awt.event.actionevent; import java.awt.event.actionlistener; import javax.swing.jbutton;

96 import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; import javax.swing.jtextfield; class MyPanel extends JPanel int x=250, y=30; public void move(int dx) this.x += dx; protected void paintcomponent(graphics g) super.paintcomponent(g); this.setbackground(color.yellow); g.setcolor(color.red); g.fillrect(x, y, 10, 200); class Myframe extends JFrame MyPanel panel; JPanel panel1; JButton b1, b2; public Myframe() setsize(500,300); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 박스움직이기 "); panel=new MyPanel(); panel1=new JPanel(); b1=new JButton(" 왼쪽으로이동 "); b2=new JButton(" 오른쪽으로이동 "); panel1.add(b1); panel1.add(b2); add(panel, BorderLayout.CENTER); add(panel1, BorderLayout.SOUTH); b1.addactionlistener(new ActionListener() public void actionperformed(actionevent e) panel.move(-10); ); b2.addactionlistener(new ActionListener() public void actionperformed(actionevent e) panel.move(10); ); setvisible(true); public class MyFrameTest public static void main(string[] arge)

97 Myframe f=new Myframe(); 5. import java.awt.font; import java.awt.event.mouseadapter; import java.awt.event.mouseevent; import java.awt.event.mouselistener; import javax.swing.jframe; import javax.swing.jlabel; class Myframe extends JFrame JLabel label; public Myframe() setsize( 700,200); setdefaultcloseoperation(jframe.exit_on_close); settitle(" 박스움직이기 "); label = new JLabel("Don't cry before you are hurt"); label.setfont(new Font("Serif", Font.BOLD Font.ITALIC, 50)); label.addmouselistener(new public void mouseexited(mouseevent arg0) // TODO Auto-generated method stub super.mouseexited(arg0); label.settext("don't cry before you are hurt"); public void mouseentered(mouseevent arg0) label.settext(" 다치기도전에울지말라 "); ); add(label); setvisible(true); public class MyFrameTest public static void main(string[] arge)

98 Myframe f=new Myframe(); p 이미지를 ImageIcon 객체로만들고버튼객체의 seticon() 메소드를사용한다. 2. ImageIcon image = new ImageIcon("sample.gif"); 3. seticon() p setselected() 2. ItemStateChanged 3. isselected() p JRadioButton, ButtonGroup 2. isselected() 3. Border 객체를인수로 setborder() 메소드를호출한다. p JTextArea 2. JTextPane 3. gettext() 4. settext() 5. selectall() p ActionEvent 2. JPasswordField 3. Integer.paseInt(tf.getText()); p button.addactionlistener(new ActionListener()

99 ); public void actionperformed(actionevent e) ta.appendtext("i\'ve clicked"); 2. appendtext(); p 스크롤페인을생성하고텍스트영역을스크롤페인에넣는다. 스크롤페인을하나의컨테이너로간주하면된다. 2. JScrollPane scroll = new JScrollPane(textArea, JScrollPane.VERTICAL_SCROLLBAR_ALWAYES, JScrollPane.HORIZONTAL_SCROLLBAR_NEVER); import javax.swing.*; import java.awt.*; import java.awt.event.*; class MyFrame extends JFrame implements ActionListener //MyFrame 클래스정의 JFrame으로부터 상속 private int sum, temp1, temp2, temp3; // 액션리스너구현 private JButton order_button, cancle_button; // 컴포넌트와컨테 이너참조변수 private JPanel down_panel; private JTextField text; WelcomePanel welcom_panel = new WelcomePanel(); // 문구, 타입, 토핑, 크기패널생성 TypePanel TypePanel = new TypePanel(); ToppingPanel ToppingPanel = new ToppingPanel(); SizePanel SizePanel = new SizePanel(); public MyFrame() // 생성자정의 this.setsize(400,400); // 프레임크기정의 this.setdefaultcloseoperation(jframe.exit_on_close); // 종료설정 this.settitle(" 피자주문 "); // 타이틀초기화 this.order_button = new JButton(" 계산 "); // 주문버튼생성 this.order_button.addactionlistener(this); // 이벤트처리등록 this.cancle_button = new JButton(" 취소 "); // 취소버튼생성

100 this.cancle_button.addactionlistener(this); // 이벤트처리등록 튼추가 this.text = new JTextField(); text.seteditable(false); text.setcolumns(6); down_panel = new JPanel(); down_panel.add(this.order_button); down_panel.add(this.cancle_button); down_panel.add(this.text); // 텍스트필드생성 // 수정불가 // 길이 6칸 // 패널생성 // 주문버튼취소버 // 텍스트필드추가 설정쪽쪽앙 this.setlayout(new BorderLayout()); // 프레임배치관리자 this.add(welcom_panel,borderlayout.north); // 웰컴패널북쪽 this.add(down_panel,borderlayout.south); // 버튼패널남 this.add(sizepanel,borderlayout.east); // 사이즈패널동 this.add(typepanel,borderlayout.west); // 타입패널서쪽 this.add(toppingpanel,borderlayout.center); // 토핑패널중 pack(); // 사이즈조절 this.setvisible(true); // 프레임화면표시 트처리시경우시저장사 public void actionperformed(actionevent e) // 액션이벤 if(e.getsource() == this.order_button) // 액션소스검출 ' 주문버튼 if(this.typepanel.combo.isselected()) // 라디오버튼검사 temp1 = 100; // 해당라디오버튼눌렷을 // 각라이오버튼의비용을임 else if(this.typepanel.potato.isselected()) temp1 = 200; else if(this.typepanel.bulgogi.isselected()) temp1 = 300; // 토핑라디오버튼검 if(this.toppingpanel.pepper.isselected()) temp2 = 400; else if(this.toppingpanel.cheese.isselected()) temp2 = 500; else if(this.toppingpanel.peperoni.isselected()) temp2 = 600;

101 검사 우 else if(this.toppingpanel.bacon.isselected()) temp2 = 700; // 사이즈라디오버튼 if(this.sizepanel.samll.isselected()) temp3 = 1000; else if(this.sizepanel.medium.isselected()) temp3 = 5000; else if(this.sizepanel.large.isselected()) temp3 = 10000; sum = temp1 + temp2 + temp3; // 총가격합계저장 this.text.settext(""+sum); // 텍스트필드출력 if(e.getsource() == this.cancle_button) // 액션소스가취소버튼일경 temp1 = 0; temp2 = 0; temp3 = 0; sum = 0; this.text.settext(""+sum); // 전부초기화후초기값출력 class WelcomePanel extends JPanel // 웰컴패널클래스정의 JPanel 상속 private JLabel message; // 메세지라벨참조변수 public WelcomePanel() // 생성자 message = new JLabel(" 자바피자에오신것을환영합니다."); add(message); // 라벨을생성후객체에추가 class TypePanel extends JPanel // 타입패널정의 JPanel 상속 private JRadioButton combo,potato, bulgogi; // 라디오버튼정의 private ButtonGroup bg; // 버튼그룹정의 public TypePanel() setlayout(new GridLayout(3,1)); // 생성자 // 배치관리자정의 묶기 combo = new JRadioButton(" 콤보 ",true); potato = new JRadioButton(" 포테이토 "); bulgogi = new JRadioButton(" 불고기 "); bg = new ButtonGroup(); bg.add(combo); bg.add(potato); bg.add(bulgogi); // 라디오버튼생성 // 버튼그룹정의후 튼그룹정리 setborder(borderfactory.createtitledborder(" 종류 ")); / / 버

102 추가 add(combo); // 객체에라디오버튼 add(potato); add(bulgogi); 상속 조변수 변수 class ToppingPanel extends JPanel // 토핑패널정의 JPanel private JRadioButton pepper, cheese, peperoni, bacon; // 라디오버튼참 private ButtonGroup bg; // 버튼그룹참조 public ToppingPanel() // 생성자 setlayout(new GridLayout(4,1)); // 배치관리자일렬 성 pepper = new JRadioButton(" 피망 ",true); // 라디오버튼생 cheese = new JRadioButton(" 치즈 "); peperoni = new JRadioButton(" 페페로니 "); bacon = new JRadioButton(" 베이컨 "); 묶기 bg = new ButtonGroup(); bg.add(pepper); bg.add(cheese); // 버튼그룹생성후라디오버튼 bg.add(peperoni); bg.add(bacon); // 버튼그룹정리 setborder(borderfactory.createtitledborder(" 추가토핑 ")); 추가 add(pepper); // 객체에라디오버튼 add(cheese); add(peperoni); add(bacon); 속 수 class SizePanel extends JPanel // 사이즈패널정의 JPanel 상 private JRadioButton samll, medium, large; // 라디오버튼참조변 private ButtonGroup bg; // 버튼그룹참조변수 public SizePanel() setlayout(new GridLayout(3,1)); samll = new JRadioButton("Small",true); medium = new JRadioButton("Medium"); large = new JRadioButton("Large"); // 생성자 // 배치관리자 // 라디오버튼생성

103 bg = new ButtonGroup(); // 버튼그룹생성 bg.add(samll); bg.add(medium); bg.add(large); // 버튼그룹정리 setborder(borderfactory.createtitledborder(" 크기 ")); public class exam1 add(samll); add(medium); add(large); public static void main(string[] args) MyFrame mf = new MyFrame(); // 객체에라디오버튼추가 // 드라이버클래스 1. (1) 참 (2) 참 (3) 거짓 (4) 참 (5) 거짓 (6) 거짓 2. ImageIcon image = new ImageIcon("image.gif");

104 JLabel label = new JLabel(" 이미지레이블 "); label.seticon(image); 3. (1) tf.gettext() (2) tf.settext(""); (3) ActionEvent 가발생한다. (4) ItemEvent (5) ActionEvent 가발생한다. 4. (1) JButton button= newjbutton(); (2) JTextField atextfield = new JTextField(" 초기텍스트 ", 20); (3) JTextComponent t = new JTextArea(20, 10); (4) JTextArea textarea = new JTextArea(20, 30); new JScrollPane().add(textArea); (5) panel.setborder( BorderFactory.createTitledBorder(" 크기 ")); 1. import java.awt.*; import java.awt.event.*; import javax.swing.*; public class NumberGameextends JFrame private int randomnum; private JTextField inputfield; private JLabel guidelabel; private JButton retrybutton; private JButton exitbutton; public NumberGame() // 부모클래스생성자명시적호출 super(" 숫자게임 "); //top 패널에들어갈컴포넌트구성 JLabel infolabel = new JLabel(" 숫자를추측하시오 : "); inputfield = new JTextField(10); inputfield.addactionlistener(new TextFieldActionListener()); //top 패널구성 JPanel toppanel = new JPanel(); toppanel.add(infolabel); toppanel.add(inputfield);

105 //middle 패널에들어갈레이블구성 guidelabel = new JLabel(" 숫자를입력하시오."); guidelabel.setbackground(color.white); guidelabel.setopaque(true);// 레이블을불투명하게 //middle 패널구성 JPanel middlepanel = new JPanel(); middlepanel.add(guidelabel); //low 패널에들어갈버튼구성 retrybutton = new JButton(" 새게임 "); exitbutton = new JButton(" 종료 "); retrybutton.addactionlistener(new ButtonActionListener()); exitbutton.addactionlistener(new ButtonActionListener()); //low 패널구성 JPanel lowpanel = new JPanel(); lowpanel.add(retrybutton); lowpanel.add(exitbutton); // 메인패널구성 JPanel mainpanel = new JPanel(); mainpanel.setlayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS)); mainpanel.add(toppanel); mainpanel.add(middlepanel); mainpanel.add(lowpanel); add(mainpanel); // 랜덤넘버와프레임설정 setrandomnum(); setdefaultcloseoperation(exit_on_close); pack(); setvisible(true); //TextField에들어갈액션리스너 private class TextFieldActionListener implements public void actionperformed(actionevent e) // TODO Auto-generated method stub try if(integer.parseint(inputfield.gettext()) < randomnum) guidelabel.settext(" 너무낮습니다!"); guidelabel.setbackground(color.red); else if(integer.parseint(inputfield.gettext()) > randomnum) guidelabel.settext(" 너무높습니다!"); guidelabel.setbackground(color.red); else guidelabel.settext(" 정답입니다!"); guidelabel.setbackground(color.white);

106 catch(numberformatexception ne) guidelabel.settext(" 잘못된입력입니다!"); guidelabel.setbackground(color.red); inputfield.selectall(); //Button에들어갈액션리스너 private class ButtonActionListener implements public void actionperformed(actionevent e) // TODO Auto-generated method stub if(e.getsource() == retrybutton) setrandomnum(); guidelabel.settext(" 숫자를입력하시오."); inputfield.settext(""); else if(e.getsource() == exitbutton) System.exit(0); // 접근자 public int getrandomnum() return randomnum; // 설정자 public void setrandomnum() randomnum = (int)(math.random()*100)+1; public static void main(string[] args) new NumberGame(); 2. import java.awt.*; import java.awt.event.*; import javax.swing.*; public class TextConverter extends JFrame JButton converter; JButton canceler; JTextArea textin; JTextArea textout; public TextConverter() super(" 텍스트변환 ");

107 // 텍스트에어리어 textin = new JTextArea(10, 14); textout = new JTextArea(10, 14); textin.setlinewrap(true);// 자동줄바꿈 textout.setlinewrap(true); textout.setenabled(false);// 비활성화 // 텍스트에어리어를관리할패널 JPanel textareapanel = new JPanel(new GridLayout(1, 2, 20, 20)); textareapanel.add(textin); textareapanel.add(textout); // 버튼 converter = new JButton(" 변환 "); canceler = new JButton(" 취소 "); converter.addactionlistener(new ButtonActionListener()); canceler.addactionlistener(new ButtonActionListener()); // 버튼패널 JPanel buttonpanel = new JPanel(new FlowLayout()); buttonpanel.add(converter); buttonpanel.add(canceler); // 메인패널 JPanel mainpanel = new JPanel(new BorderLayout(10, 10)); mainpanel.add(borderlayout.center, textareapanel); mainpanel.add(borderlayout.south, buttonpanel); // 프레임설정 setlayout(new FlowLayout(FlowLayout.CENTER, 20, 20)); add(mainpanel); pack(); setdefaultcloseoperation(exit_on_close); setvisible(true); // 버튼의액션이벤트를처리할버튼액션리스너클래스 private class ButtonActionListener implements public void actionperformed(actionevent e) // TODO Auto-generated method stub if(e.getsource() == converter) textout.settext(""); String result = toenglish(textin.gettext()); textout.append(result); if(e.getsource() == canceler) textout.settext(""); // 영어를한국어로변환하는메소드 private String toenglish(string korean) String result = korean; result = result.replace(" 텍스트 ", "Text");

108 result = result.replace(" 영어 ", "English"); return result; public static void main(string[] args) TextConverter t=new TextConverter(); 3. import java.awt.font; import java.awt.gridlayout; import java.awt.event.itemevent; import java.awt.event.itemlistener; import javax.swing.imageicon; import javax.swing.jcheckbox; import javax.swing.jcomponent; import javax.swing.jframe; import javax.swing.jlabel; import javax.swing.jpanel; public class CheckBoxDemo extends JPanel implements ItemListener JCheckBox[] buttons = new JCheckBox[4]; String[] fruits = " 엔진오일교환 ", " 자동변속기오일교환 ", " 에어콘필터교환 ", " 타이어교환 "; int[] prices = 45000, 80000, 30000, ; int money=0; JLabel label; public CheckBoxDemo() super(); // 체크박스생성 for (int i = 0; i < 4; i++) buttons[i] = new JCheckBox(fruits[i]); buttons[i].additemlistener(this); for (int i = 0; i < 4; i++) add(buttons[i]); label = new JLabel(" 현재까지의가격은 "+money+" 입니다."); label.setfont(new Font("Serif", // 레이블에폰트를설정한다. Font.BOLD Font.ITALIC, 30));

109 add(label); /** 체크박스의아이템이벤트를처리한다. */ public void itemstatechanged(itemevent e) Object source = e.getitemselectable(); for (int i = 0; i < 4; i++) if (source == buttons[i]) if (e.getstatechange() == ItemEvent.DESELECTED) money -= prices[i]; else money += prices[i]; label.settext(" 현재까지의가격은 "+money+" 입니다."); public static void main(string[] args) JFrame frame = new JFrame("CheckBoxDemo"); frame.setdefaultcloseoperation(jframe.exit_on_close); JComponent newcontentpane = new CheckBoxDemo(); newcontentpane.setopaque(true); frame.setcontentpane(newcontentpane); frame.setsize(500, 200); frame.setvisible(true); 4. 생략 (3 번문제와유사 ) 5. import java.awt.canvas; import java.awt.color; import java.awt.dimension; import java.awt.graphics; import java.awt.event.mouseevent; import java.awt.event.mouselistener; import java.util.random; import javax.swing.jframe; import javax.swing.jpanel; class MyPanel extends JPanel private static final int EMPTY = 0,X_PIECE = 1,O_PIECE = 2;

110 private int[][] gamegrid = new int[3][3]; private boolean xturn; private Random random; private boolean gamerunning; private int gameresult; public MyPanel() setpreferredsize(new Dimension(256,256)); setbackground(color.white); addmouselistener(new GameListener()); random = new Random(); cleargrid(); gamerunning = true; private class GameListener implements MouseListener public void mousepressed(mouseevent e) public void mouseclicked(mouseevent e) int xpos = e.getpoint().x; int ypos = e.getpoint().y; if(xpos > 50 && ypos > 50 && xpos < 50+50*3 && ypos < 50+50*3) if(gamerunning == false) cleargrid(); gamerunning = true; repaint(); return; if(gamegrid[xpos/50-1][ypos/50-1]!= EMPTY) return; if(xturn) gamegrid[xpos/50-1][ypos/50-1] = X_PIECE; xturn = false; else gamegrid[xpos/50-1][ypos/50-1] = O_PIECE; xturn = true; gameresult = gameover(); if(gameresult!= 0) gamerunning = false; repaint(); public void mousereleased(mouseevent e) public void mouseentered(mouseevent e)

111 public void mouseexited(mouseevent e) public void cleargrid() for(int y = 0;y < 3;y++) for(int x = 0;x < 3;x++) gamegrid[x][y] = EMPTY; if(random.nextint(100) < 50) xturn = true; else xturn = false; int gameover() for(int x = 0;x < 3;x++) if(gamegrid[x][0] == gamegrid[x][1] && gamegrid[x][1] == gamegrid[x][2]) return gamegrid[x][0]; for(int y = 0;y < 3;y++) if(gamegrid[0][y] == gamegrid[1][y] && gamegrid[1][y] == gamegrid[2][y]) return gamegrid[0][y]; if(gamegrid[0][0] == gamegrid[1][1] && gamegrid[1][1] == gamegrid[2][2]) return gamegrid[0][0]; if(gamegrid[2][0] == gamegrid[1][1] && gamegrid[0][2] == gamegrid[1][1]) return gamegrid[2][0]; for(int y = 0;y < 3;y++) for(int x = 0;x < 3;x++) if(gamegrid[x][y] == 0) return 0; return 3; public void paintcomponent(graphics g) g.clearrect(0,0,getwidth(),getheight()); g.setcolor(color.black); for(int y = 1;y < 3;y++) g.drawline(50,y*50+50,50+50*3,y*50+50); for(int x = 1;x < 3;x++) g.drawline(x*50+50,50,x*50+50,50+50*3); for(int y = 0;y < 3;y++) for(int x = 0;x < 3;x++) if(gamegrid[x][y] == X_PIECE) g.setcolor(color.blue); g.drawline(50+x*50,50+y*50,50+x*50+50,50+y*50+50); g.drawline(50+50+x*50,50+y*50,50+x*50,50+y*50+50);

112 if(gamegrid[x][y] == O_PIECE) g.setcolor(color.red); g.drawoval(50+x*50,50+y*50,50,50); g.setcolor(color.black); if(gamerunning) if(xturn) g.drawstring("x 차례입니다.",10,220); else g.drawstring("o 차례입니다.",10,220); else if(gameresult == X_PIECE) g.drawstring("x가이겻습니다!",10,220); if(gameresult == O_PIECE) g.drawstring("o가이겼습니다!",10,220); if(gameresult == 3) g.drawstring(" 비겼습니다!",10,220); g.drawstring(" 새로운게임을시작하려면클릭하세요.",10,240); public class TicTacToeGame extends JFrame public static void main(string[] args) TicTacToeGame tictactoe = new TicTacToeGame(); tictactoe.settitle("tic-tac-toe"); tictactoe.setdefaultcloseoperation(jframe.exit_on_close); MyPanel gameboard = new MyPanel(); tictactoe.add(gameboard); tictactoe.pack(); tictactoe.setlocationrelativeto(null); tictactoe.setvisible(true);

113 6. import javax.swing.*; import java.awt.*; import java.awt.event.*; class Login extends JFrame implements ActionListener JButton SUBMIT; JPanel panel; JLabel label1, label2; final JTextField text1, text2; Login() label1 = new JLabel(); label1.settext(" 이메일 "); text1 = new JTextField(30); label2 = new JLabel(); label2.settext(" 비밀번호 "); text2 = new JPasswordField(30); SUBMIT = new JButton(" 로그인 "); panel = new JPanel(new GridLayout(0, 1)); panel.add(label1); panel.add(text1); panel.add(label2); panel.add(text2); panel.add(submit); add(panel, BorderLayout.CENTER); SUBMIT.addActionListener(this); settitle("login FORM"); public void actionperformed(actionevent ae) String value1 = text1.gettext(); String value2 = text2.gettext(); if (value1.equals("hong") && value2.equals("1111")) System.out.println(" 로그인성공 "); else

114 System.out.println(" 로그인실패 "); public class LoginDemo public static void main(string arg[]) Login frame = new Login(); frame.setsize(400, 200); frame.setvisible(true); p.6 1. list.setborder(borderfactory.createlineborder(color.black, 1)); 2. ListSelectionModel.SINGLE_SELECTION ListSelectionModel.SINGLE_INTERVAL_SELECTION ListSelectionModel.MULTIPLE_INTERVAL_SELECTION 예를들어서단일선택모드로변경하려면다음과같은문장을사용한다. list.setselectionmode(listselectionmodel.single_selection); p combo.additem("dog"); 2. ActionEvent 3. getselecteditem() p SpinnerListModel, SpinnerNumberModel, SpinnerDateModel

115 2. 적합한값들만입력받는다. p ChangeEvent 2. getvalue() p add() 2. TreeSelectionEvent 3. getuserobject() 1. import javax.swing.*; import java.awt.*; import java.awt.event.*; class MyFrame extends JFrame implements ActionListener JTextField tf1=new JTextField(10); JTextField tf2=new JTextField(10); JTextField tf3=new JTextField(10); JButton b=new JButton(" 입력 "); public MyFrame() JPanel panel1 = new JPanel(); panel1.add(new JLabel(" 중간고사 ")); panel1.add(tf1); panel1.add(new JLabel(" 기말고사 ")); panel1.add(tf2); JPanel panel2 = new JPanel(); panel2.add(b); JPanel panel3 = new JPanel(); panel3.add(new JLabel(" 총점은 ")); panel3.add(tf3); panel3.add(new JLabel(" 입니다.")); add(panel1, BorderLayout.NORTH); add(panel2, BorderLayout.CENTER); add(panel3, BorderLayout.SOUTH); b.addactionlistener(this); public void actionperformed(actionevent ae) String value1 = tf1.gettext(); String value2 = tf2.gettext();

116 int mid_s = Integer.parseInt(value1); int final_s = Integer.parseInt(value2); tf3.settext(""+(mid_s+final_s)); public class MyFrameTest public static void main(string arg[]) MyFrame frame = new MyFrame(); frame.setsize(400, 150); frame.setvisible(true); 2. import java.awt.*; import java.awt.event.*; import javax.swing.*; class Chapter21_Frameextends JFrame // 클래스안에공통으로사용될필드 String[] petstrings="bird","cat","dog","robbit","pig";// 하는배열 리스트의목록을저장 // 프레임의설정과컴포넌트를불러오는생성자 public Chapter21_Frame() Com C=new Com(); // 콤보박스와그림을배치하고, 이벤트를처리하는 객체선언 settitle("chapter21");

117 setdefaultcloseoperation(jframe.exit_on_close); C.Panel1(); // 콤보박스를배치하는매서드호출 C.Panel2(); // 그림을배치하는매서드호출 pack(); setvisible(true); class Com implements ActionListener JComboBox petlist; // 목록을선택할콤보박스 JLabel label; // 사진이들어갈레이블 public void Panel1() JPanel Pan=new JPanel(); petlist=new JComboBox(petStrings); // 리스트의목록으로콤보박스객 체를생성한다. petlist.setselectedindex(4); // 콤보박스의기본적인선택값은리스트의 5번째로한다. petlist.addactionlistener(this); // 콤보박스에서이벤트가발생하면현재 클래스안의액션리스너로이벤트를처리 Pan.add(petList); add(pan,borderlayout.page_start); public void Panel2() JPanel Pan=new JPanel(); label=new JLabel(); // 스크롤을항상보이게생성한다. JScrollPane scroll=new JScrollPane(label,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCRO LLBAR_ALWAYS); label.seticon(new ImageIcon(petStrings[4]+".jpg")); // 레이블에서 리스트의 5번째와같은이름의이미지를출력한다. Pan.add(scroll); add(pan,borderlayout.page_end); public void actionperformed(actionevent e) JComboBox cb=(jcombobox)e.getsource(); String petname=(string)cb.getselecteditem(); // 이벤트발생시받아온 매개변수를문자열로변환한다. updatelabel(petname); // 변환한문자열을매개변수로레이블의그림을바 꿔주는매서드를호출한다. void updatelabel(string petname) label.seticon(new ImageIcon(petName+".jpg")); // 이미지를 매개변수와 같은이름의이미지로교체한다. class Chapter21 public static void main(string[] args)

118 (1) Chapter21_Frame Chapter21_F=new Chapter21_Frame(); import java.awt.borderlayout; import javax.swing.*; import javax.swing.event.listselectionevent; import javax.swing.event.listselectionlistener; class Chapter21_Frameextends JFrame // 클래스안에공통으로사용될필드 String[] petstrings="bird","cat","dog","robbit","pig";// 하는배열 리스트의목록을저장 // 프레임의설정과컴포넌트를불러오는생성자 public Chapter21_Frame() Com C=new Com(); // 리스트와그림을배치하고, 이벤트를처리하는 객체선언 settitle("chapter21"); setdefaultcloseoperation(jframe.exit_on_close); C.Panel1(); // 리스트를배치하는매서드호출 C.Panel2(); // 그림을배치하는매서드호출 다. pack(); setvisible(true); class Com implements ListSelectionListener JList petlist; // 목록을선택할리스트 JLabel label; // 사진이들어갈레이블 public void Panel1() JPanel Pan=new JPanel(); petlist=new JList(petStrings); // 리스트의목록으로리스트객체를생성한

119 petlist.setselectedindex(4); // 리스트의기본적인선택값은리스트의 5번째로한다. petlist.addlistselectionlistener(this); // 리스트에서이벤트가발생하면 현재이벤트를처리 Pan.add(petList); add(pan,borderlayout.page_start); public void Panel2() JPanel Pan=new JPanel(); label=new JLabel(); // 스크롤을항상보이게생성한다. JScrollPane scroll=new JScrollPane(label,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCRO LLBAR_ALWAYS); label.seticon(new ImageIcon(petStrings[4]+".jpg")); // 레이블에서 리스트의 5번째와같은이름의이미지를출력한다. Pan.add(scroll); add(pan,borderlayout.page_end); public void valuechanged(listselectionevent e) JList cb=(jlist)e.getsource(); String petname=(string)cb.getselectedvalue(); // 이벤트발생시받아온 매개변수를문자열로변환한다. updatelabel(petname); // 변환한문자열을매개변수로레이블의그림을바 꿔주는매서드를호출한다. void updatelabel(string petname) label.seticon(new ImageIcon(petName+".jpg")); // 이미지를 매개변수와 같은이름의이미지로교체한다. class Chapter21 public static void main(string[] args) Chapter21_Frame Chapter21_F=new Chapter21_Frame(); 문제가없음!

120 p 관련있는클래스를서로묶기위하여 2. 디폴트패키지에자동으로속하게된다. p (1) graphics.rectangle 라고적어준다. (2) import graphics.rectangle; 를소스파일의첫부분에추가한다. (3) import graphics.*; 를소스파일의첫부분에추가한다. 2. 인터넷도메인이름의역순으로하는것이좋다. p 관련된클래스들을묶을수있고, 기능에따라클래스를패키지로분류할수있고, 같은클래스이름을여러패키지가사용할수있고, 패키지별로접근에제약을가할수있다. 2. 인터넷도메인이름의역순으로하는것이좋다. 3. kr.ac.hu.xxx 4. ( 작업디렉토리 )/company/project/ 5. package project.server; 6. javac 에서 -d 옵션을사용한다. p Buffer,ByteBuffer,ByteOrder,CharBuffer,DoubleBuffer,FloatBuffer,IntBuffer,LongBuffer, MappedByteBuffer,ShortBuffer 등의클래스가정의되어있다.

121 p 정수 10 은객체가아니다. Integer(10) 은객체이다. 2. String 클래스는상수문자열, 즉변경이불가능한문자열을나타낼때사용되고 StringBuffer 는내부적으로문자열을저장하는메모리를가지고있어변경가능한문자열을저장한다. p Random random = new Random(); System.out.println(random.nextInt(999)+1); 2. Date d = new Date(); System.out.println(d); 1. (1) package movie; (2) movie.director d = new movie.director(); (3) import movie.*; 2. (1) 각파일의첫번째줄에서패키지를지정하여야한다. Client.java: package mysrc.client; Server.java: package mysrc.server;: Utilities.java: package mysrc.util; (2) 먼저 mysrc 디렉토리안에 client, server, util 디렉토리를생성한다. mysrc/client/ 안에 Client.java 파일을위치시킨다. mysrc/server/ 안에 Server.java 파일을위치시킨다. mysrc/util/ 안에 Utilities.java 파일을위치시킨다. (3) 예를들어서 util 패키지를사용하는소스파일이면다음중하나의방법을선택한다. import mysrc.util.*; 또는 import mysrc.shared.utilities; 3. (1)

122 Random random = new Random(); System.out.println(random.nextInt(9)+1); (2) import java.util.*; public class Test public static void main(string[] args) StringTokenizer st = new StringTokenizer("By doubting we come at the truth"); while(st.hasmoretokens()) System.out.println(st.nextToken()); (3) import java.util.*; public class Test public static void main(string[] args) Calendar d = Calendar.getInstance(); System.out.print(d.get(Calendar.YEAR)+ " 년 "); System.out.print(d.get(Calendar.MONTH)+1+" 월 "); System.out.print(d.get(Calendar.DATE)-1+" 일 "); (4) import java.util.arrays; public class Test public static void main(string[] args) int[] array = 9,4,5,6,2,1; Arrays.sort(array); for(int i = 0; i < array.length; i++) System.out.print(array[i]); (5) int s = Integer.parseInt("12345"); (6) System.out.println(obj.class.getName()); 4. (1) Calendar d = Calendar.getInstance(); (2) 오류없음!(auto-boxing 이일어나게됨 ) (3) Integer i = new Integer(100); (4) 오류없음! (5) 오류없음! 5. public class Test public static void main(string[] args) ; (1) Random random = new Random(); System.out.println(random.nextInt(100)); (2) StringTokenizer st = new StringTokenizer(" ", "-"); while(st.hasmoretokens()) System.out.println(st.nextToken());

123 (3) Calendar d = Calendar.getInstance(); System.out.println(d); (4) Test obj = new Test(); System.out.println("The class of " + obj + " is " + obj.getclass().getname()); (5) for(int i = 0; i<= 90; i +=5) System.out.println(Math.sin(Math.toRadians((double)i))); 1. package game; import java.util.random; public class Die private int value; private int num; Random r = new Random(); public Die() value = 1; public int roll() num = (r.nextint(5)+1); return num; public void setvalue(int v) value = v; public String tostring() return (" 현재주사위상태 : " + roll()); public static void main(string[] args) Die d = new Die(); System.out.println(d.toString()); 2. package rps; import java.util.*; public class Game public static void main(string[] args) Random r = new Random(); Scanner s = new Scanner(System.in); int num1, num2;

124 System.out.println(" 하나를선택하시요 : 가위 (0), 바위 (1), 보 (2) :"); num1 = s.nextint(); num2 = r.nextint(3); if(num2 == 0) System.out.println(" 컴퓨터는가위를냈습니다."); else if(num2 == 1) System.out.println(" 컴퓨터는바위를냈습니다."); else System.out.println(" 컴퓨터는보를냈습니다."); if(num1==0) if(num2 == 1) System.out.println(" 컴퓨터가이겼습니다 "); else if(num2 == 2) System.out.println(" 당신이이겼습니다."); else System.out.println(" 비겼습니다."); else if(num1 == 1) if(num2 == 0) System.out.println(" 당신이이겼습니다."); else if(num2 == 2) System.out.println(" 컴퓨터가이겼습니다."); else System.out.println(" 비겼습니다."); else if(num2 == 0) System.out.println(" 컴퓨터가이겼습니다 "); else if(num2 == 1) System.out.println(" 당신이이겼습니다."); else System.out.println(" 비겼습니다."); 3. import java.util.*; import java.util.arrays; public class StrSort public static void main(string[] args) Scanner s = new Scanner(System.in); int count = 0, i = 0; String[] ars = new String[100]; System.out.println(" 문자열을입력하시요 : "); String str = s.nextline(); StringTokenizer st = new StringTokenizer(str);

125 while(st.hasmoretokens()) ars[i] = st.nexttoken(); System.out.println(ars[i]); count++; i++; System.out.println(" 모두 " + count + " 개의단어가있습니다."); Arrays.sort(ars); StringTokenizer st2 = new StringTokenizer(str); System.out.println("====== sort ======"); while(st2.hasmoretokens()) System.out.println(st2.nextToken()); p 으로나누는경우, 배열의인덱스가한계를넘는경우, 하드웨어에러등 2. 프로그램에서오류를처리한후에계속실행하는것이가능하다. 3. int[] array = new int[10]; try array[11] = 0; catch(arrayindexoutofboundsexception e) System.out.println(" 배열의범위를벗어났습니다."); 4. int[] array = new int[10]; try array[11] = 0; catch(arrayindexoutofboundsexception e) System.out.println(" 배열의범위를벗어났습니다."); finally array = null;

126 p Error 는시스템에서발생하는심각한오류이고, RuntimeException 은프로그래밍시에흔히발생할수있는일반적인실행오류를나타낸다. 2. RuntimeException 을제외한모든 Exception 3. RuntimeException 은프로그래머가방지할수있다. p try/catch 블록을이용하여서처리한다. 2. throws 를사용하여메소드가예외를발생한다고정의할수있다. 3. 메소드가예외를발생한다는것을의미한다. p class DiskFailureException extends Exception public MyException() super( "DiskFailure!" ); 2. class NegativeNumberException extends Exception public NegativeNumberException() super(" 음수는입력할수없음 ");... int score; int tot = 0; try for(int i = 0; i < 3; i++) score = scan.nextint(); if(score < 0) throw new NegativeNumberException(); tot += score; System.out.println(" 평균은 " + tot/3.0 + " 입니다."); catch(negativenumberexception e) System.out.println(e.toString()); 1. (1) import java.util.scanner; import java.io.file;

127 import java.io.filenotfoundexception; public class FileErrorTest public static void main(string[] args) try Scanner in = new Scanner(new File("data.txt")); catch (FileNotFoundException e) // TODO Auto-generated catch block e.printstacktrace(); (2) import java.util.scanner; import java.io.file; import java.io.filenotfoundexception; public class FileErrorTest public static void main(string[] args) throws FileNotFoundException Scanner in = new Scanner(new File("data.txt")); 2. import java.util.scanner; public class ExceptionTest public static void main(string[] args) int[] list; int sum = 0, count; try Scanner sc = new Scanner(System.in); System.out.print(" 정수의개수 : "); count = sc.nextint(); list = new int[count]; for(int i=0; i<count; i++) System.out.print(" 정수를입력하시오 : "); list[i] = sc.nextint(); for(int i=0;i<count; i++) sum += list[i]; System.out.println(" 평균은 "+ sum/count); catch (ArithmeticException e) e.printstacktrace(); catch (NegativeArraySizeException e) e.printstacktrace(); catch (ArrayIndexOutOfBoundsException e)

128 e.printstacktrace(); catch (NullPointerException e) e.printstacktrace(); 1. 오류와발생되는예외를올바르게짝지으시오. Ÿ int[] list; list[0] = 0; -> 컴파일오류, 배열은초기화되지않았고컴파일되지않는다. Ÿ 자바가상기계가클래스를찾을수없는경우 -> error Ÿ 파일을읽던프로그램이파일의끝에도달한경우 -> 예외가아니다. 스트림을읽을때는언젠가는스트림의끝에도달하리라는것을예상할수있다. 예외는예상치못한경우에사용한다. Ÿ 파일의끝에도달했는데도파일을읽으려고시도 -> 체크예외 (checked exception) 2. try System.out.println(list[size]); // 배열 list의크기가 size라고가정한다. catch (ArrayIndexOutOfBoundsException e) e.printstacktrace(); 3. 합법적인코드이고또한대단히유용하다. 만약 try 블록에있는코드가오류가발생되어서여러개의출구경로를가진다고가정하자. 하지만 finally 블록에있는코드는어떠한경우에도실행된다. 따라서반드시실행되어야하는코드는 finally 블록에넣는것이좋다. 예를들어서입출력스트림을닫는코드가여기에해당한다. 4. 이예외처리기는거의모든종류의예외를잡는다. 따라서어떤종류의예외인지를알기가힘들다. 5. 첫번째예외처리기는 Exception 타입의예외를잡는다. 따라서모든종류의예외는잡는다. 따라서두번째예외처리기는실행되지못한다. 6. 숫자형식오류 finally 7. 배열크기음수오류

129 8. (1) java.lang.arrayindexoutofboundsexception (2) java.lang.nullpointerexception (3) java.lang.numberformatexception: For input string: "abc" (4) java.lang.classcastexception: java.lang.object cannot be cast to java.lang.integer 1. (1) java.lang.arrayindexoutofboundsexception (2) try int i = array[10]; catch (ArrayIndexOutOfBoundsException e) e.printstacktrace(); (3) public static void sub() throws ArrayIndexOutOfBoundsException int[] array = new int[10]; int i = array[10]; 2. class MyException extends Exception public MyException(String message) super(message); public class MyExceptionTest public static void checknegative(int number) throws MyException if (number < 0) throw (new MyException(" 음수는안됩니다.")); System.out.println(" 다행히음수가아니군요 "); public static void main(string[] args) try checknegative(1); checknegative(-1); catch (MyException ex) ex.printstacktrace(); 3. import java.util.scanner; class NotFoundExecption extends Exception public NotFoundExecption() super(" 배열에서찾을수없습니다.");

130 public class Lab2 public static int searcharray(int array[], int data) throws NotFoundExecption for(int i=0;i<array.length;i++) if( array[i] == data ) return i; throw new NotFoundExecption(); public static void main(string[] arge) Scanner sc=new Scanner(System.in); int[] a=0,1,2,3,4,5,6,7,8,9; int data=sc.nextint(); try searcharray(a, data); catch (NotFoundExecption e) // TODO Auto-generated catch block e.printstacktrace(); 4. import java.util.scanner; class NegativeBalanceException extends Exception public NegativeBalanceException(String message) super(message); class BankAccount private int balance=0; public int getbalance() return balance; public void setbalance(int balance) this.balance = balance; public void deposit(int amount) balance += amount; public void withdraw(int amount) throws NegativeBalanceException if( balance < amount ) throw new NegativeBalanceException(" 잔고가음수입니다."); balance -= amount;

131 public class BankAccountTest public static void main(string[] arge) BankAccount ba = new BankAccount(); ba.deposit(100); try ba.withdraw(200); catch (NegativeBalanceException e) // TODO Auto-generated catch block e.printstacktrace(); NegativeBalanceException: 잔고가음수입니다. at BankAccount.withdraw(BankAccountTest.java:25) at BankAccountTest.main(BankAccountTest.java:35) p 참조되는데이터의정확한타입을알수없기때문이다. 2. Box<Rectangle> b = new Box<Rectangle>(); 3. class Point<T> private T x; private T y; public T gety() return y; public T getx() return x; public void setx(t x) this.x = x; public void sety(t y) this.y = y; p public <T> void sub(t d) public class Test

132 public static <T> void displayarray(t[] a) if (a == null a.length == 0) return; for (int i = 0; i < a.length; i++) System.out.println(a[i]); public static void main(string[] args) Integer[] a = 1, 2, 3, 4, 5; Test.<Integer>displayArray(a); p 리스트 (list), 스택 (stack), 큐 (queue), 집합 (set), 해쉬테이블 (hash table) 2. 프로그램에서자료들을저장할때사용한다. p p 크기가고정되어있지않다. 2. List 인터페이스 3. 컬렉션객체들이인터페이스를구현하였기때문이다. 4. * 일반적인 for 루프 * for-each 루프 * 반복자사용 p.556

133 1. ArrayList 는근본적으로배열을사용한다. LinkedList 는연결리스트를사용한다. 2. 리스트의중간에삽입이나삭제가많은경우 p 중복을허용하지않으면서항목들의리스트가필요한애플리케이션 2. Set 은항목들의중복을서용하지않는다. List 는항목들의중복을허용한다. p 키 (key), 값 (value) 2. put(): 데이터를저장한다. get(): 데이터를꺼내온다. p 배열을생성한후에배열을가지고 List 객체를만든다. 이객체를 Collection 의정적메소드 sort() 로전달하면된다. 2.

134 1. (1) ArrayList<Double> list = new ArrayList<Double>(); (2) 컬렉션에저장된항목들을순차적으로방문할때 (3) 리스트 (list) 는중복을허용하고집합 (set) 은중복을허용하지않는다. (4) Map 2. * 자바컴파일러는컴파일시간에제네릭코드에대하여타입을검사할수있다. * 제네릭을이용하면타입을매개변수처럼간주할수있다. * 제네릭을이용하여서제네릭알고리즘을구현할수있다. 3. > 연산자는기초자료형에만적용된다. 4. public final class MyAlgorithm public static <T> void swap(t[] a, int i, int j) T temp = a[i]; a[i] = a[j]; a[j] = temp; 5. (1) public class Stack <T> private T[] stack; public void push(t data)... public T pop()... (2) Stack<String> s = new Stack<String>(); 6. (1) [ 사과, 배, 바나나, 포도 ] (2) [ 사과, 배, 자몽, 바나나, 포도 ] (3) 바나나 (4) [ 사과, 자몽, 바나나, 포도 ] (5) true (6) 0 7. (1) for(int i=0;i<list.length;i++) System.out.println(list[i]); (2) for(double data; list) System.out.println(data);

135 (3) Iterator e = list.iterator(); while(e.hasnext()) d = (Double)e.next(); // 반복자는 Object 타입을반환! System.out.println(d); 1. import java.util.*; public class RandomList<T> Random r = new Random(); String[] sample = "i", "walk", "the", "line"; List<T> list = (List<T>) Arrays.asList(sample); public void add(t item) list.add(item); public T select() int num = r.nextint(list.size()); return list.get(num); 2. 평균을구할때 double 형으로변환하여계산한다. class MyMath<T> extends Number> double v=0.0; public double getaverage(t[] a) for (int i = 0; i < a.length; i++) v = v + a[i].doublevalue(); return v/a.length; public class Test public static void main(string[] args) Integer[] list = 1, 2, 3, 4, 5, 6 ; MyMath<Integer> m = new MyMath<Integer>(); System.out.println(m.getAverage(list)); 3. class MyPair<T>

136 private T str1, str2; public MyPair(T s1, T s2) str1 = s1; str2 = s2; public void getstr1(t s1) str1 = s1; public void getstr2(t s2) str2 = s2; public T setstr1() return str1; public T setstr2() return str2; public String tostring() return "str1 : " + str1 + " str2 : " + str2; public class MyPairTest public static void main(string[] args) MyPair<String> fruit = new MyPair<String>(" 사과 ", " 포도 "); System.out.println(fruit.toString()); 4. public class Test public static <T> void displayarray(t a) System.out.println(a.getClass().getName()); public static void main(string[] args) int x=0; float y=0.0f; Test.<Object>displayArray(x); Test.<Object>displayArray(y); java.lang.integer java.lang.float 오토박싱에의하여 int 와 float 가 Integer 객체와 Float 객체로자동변환된다. 5. import java.util.arraylist; import java.util.collections;

137 import java.util.scanner; public class Test public static void main(string[] args) ArrayList<Double> list = new ArrayList<Double>(); Scanner sc = new Scanner(System.in); 심사위원의점수 : 1 심사위원의점수 : 2 심사위원의점수 : 3 심사위원의점수 : 4 심사위원의점수 : 5 심사위원의점수 : 6 심사위원의점수 : 7 심사위원의점수 : 8 심사위원의점수 : 9 심사위원의점수 : 10 점수의합 : import java.util.arraylist; import java.util.collections; import java.util.scanner; for(int i=0;i<10; i++) System.out.print(" 심사위원의점수 : "); double value = sc.nextdouble(); list.add(value); double max = Collections.max(list); double min = Collections.min(list); double sum = 0.0; double value = 0.0; for(int i=0;i<10; i++) value = list.get(i); if( value!= min && value!= max ) sum += value; System.out.print(" 점수의합 : "+ sum); class Student implements Comparable<Student> public Student(String name, String address, String phone) super(); this.name = name; this.address = address; this.phone = phone; public int compareto(student s)

138 return name.compareto(s.name); public String getname() return name; public void setname(string name) this.name = name; public String getaddress() return address; public void setaddress(string address) this.address = address; public String getphone() return phone; public void setphone(string phone) this.phone = public String tostring() return "Student [name=" + name + ", address=" + address + ", phone=" + phone + "]"; String name; String address; String phone; public class Test public static void main(string[] args) ArrayList<Student> list = new ArrayList<Student>(); Scanner sc = new Scanner(System.in); for(int i=0;i<10; i++) list.add(new Student("name"+i, "address"+i, "phone"+i)); 3 "phone3")); Collections.sort(list); int pos = Collections.binarySearch(list, new Student("name3", "address3", System.out.println(pos); 7. 문제오타 : 로또번호를생성하는프로그램을작성하여보자. 로또는 1 부터 45 까지의숫자중에서 6 개를선택한다. 로또번호는중복되면안된다. 따라서집합을나타내는 HashSet 을사용하여

139 서중복을검사하여보자. Math.random() 을사용하면 0 부터 1 사이의난수를생성할수있다. 0 부터 1 사이의난수가생성되면여기에 44 를곱하고 1 을더하면 1 부터 45 사이의정수를생성할수있다. 생성된정수는 HashSet 의 contains() 메소드를이용하여서이미선택된정수인지를검사한다. import java.util.hashset; public class public String tostring() return "Lotto [set=" + set + "]"; HashSet<Integer> set = new HashSet<Integer>(); public Lotto() int d; for (int i = 0; i < 6; i++) do d = (int) (Math.random() * ); while (set.contains(d)); set.add(d); public static void main(string[] args) Lotto lotto = new Lotto(); System.out.println(lotto); Lotto [set=[16, 23, 7, 8, 26, 30]] p 프로세스는독자적으로실행이가능한환경으로일반적으로완전한자기만의자원을가진

140 다. 스레드는프로세스안에존재하여프로세스의자원을공유한다. 2. 게임프로그램 3. 데이터를공유하기때문에동기화문제가발생한다. p Thread 2. 자바에서는단일상속만가능하므로다른클래스를이미상속한클래스는스레드로만들수없다. p setpriority() 는현재스레드의우선순위를변경하고 getpriority() 는현재스레드의우선순위를반환한다. 2. 현재스레드의실행을지정된시간동안중단하게만든다 3. 현재수행가능한스레드중에서가장우선순위가높은스레드를먼저실행시킨다. 4. run() 메소드안에스레드가해야할작업을서술한다. 5. start() 메소드를호출하면 run() 이호출된다. stop() 메소드를사용하여스레드를정지시켜종료한다. 6. 다른스레드가 suspend() 를호출하는경우, 스레드가 wait() 를호출하는경우, 스레드가 sleep() 을호출하는경우, 스레드가입출력작업을하기위해대기하는경우 p 공유된데이터를여러개의스레드가동시에접근하기때문에발생한다. 2. synchronized p 스레드간의동작을일치하기위하여사용한다. 2. wait() 는어떤일이일어나기를기다릴때사용하는메소드이다 3. notifyall() 는어떤일이일어났을때이를알려주는메소드이다. 1. CPU 의시간을잘게나누어서스레드에게각슬라이스를할당한다. 2. (1) Thread 클래스를상속받아서브클래스를만들고 run() 메소드를오버라이드하는방법이다. Thread 클래스를확장하는방법은자바에서는단일상속만이가능하므로다른클래스를이미상속한클래스는스레드로만들수없다. (2) Runnable 인터페이스는스레드로실행이가능한객체들이만족하여야하는인터페이스이다. Runnable 객체는 Thread 가아닌다른클래스를상속받을수있다. 3. (1) 현재스레드의실행을지정된시간동안중단 (2) CPU 를다른스레드에게양보한다. (3) run() 을호출하여스레드를실행시킨다. 4. (1) 다음과같은출력을내면서무한반복된다.

141 (2) class Job extends Thread... (3) class Job extends Thread private String name; public Job(String name) this.name = name; public void run() byte n = 0; while (true) System.out.println(name + n++); public class Test public static void main(string[] args) Job j = new Job("Thread1"); j.start(); (4) 두개의스레드가번갈아가면서실행된다. class Job extends Thread private String name; public Job(String name) this.name = name; public void run() byte n = 0; while (true) System.out.println(name + n++); public class Test public static void main(string[] args) Job j1 = new Job("Thread1"); j1.start(); Job j2 = new Job("Thread2"); j2.start(); 5.

142 A C D 1. import java.awt.borderlayout; import java.awt.color; import java.awt.font; import java.awt.graphics; import java.awt.gridlayout; import java.awt.event.actionevent; import java.awt.event.actionlistener; import java.awt.event.windowadapter; import java.awt.event.windowevent; import java.text.decimalformat; import javax.swing.jbutton; import javax.swing.jcomponent; import javax.swing.jframe; import javax.swing.jpanel; import javax.swing.border.emptyborder; public class SecondCounterDemo extends JPanel private SecondCounterRunnable sc = new SecondCounterRunnable(); private JButton startb = new JButton(" 카운터시작 "); private JButton stopb = new JButton(" 카운터중지 "); public SecondCounterDemo() stopb.setenabled(false); startb.addactionlistener(new ActionListener() public void actionperformed(actionevent e) startb.setenabled(false); Thread counterthread = new Thread(sc, "Counter"); counterthread.start(); ); stopb.setenabled(true); stopb.requestfocus(); stopb.addactionlistener(new ActionListener() public void actionperformed(actionevent e) stopb.setenabled(false);

143 ); sc.stopclock(); startb.setenabled(true); startb.requestfocus(); JPanel innerbuttonp = new JPanel(); innerbuttonp.setlayout(new GridLayout(0, 1, 0, 3)); innerbuttonp.add(startb); innerbuttonp.add(stopb); JPanel buttonp = new JPanel(); buttonp.setlayout(new BorderLayout()); buttonp.add(innerbuttonp, BorderLayout.NORTH); this.setlayout(new BorderLayout(10, 10)); this.setborder(new EmptyBorder(20, 20, 20, 20)); this.add(buttonp, BorderLayout.WEST); this.add(sc, BorderLayout.CENTER); public static void main(string[] args) SecondCounterDemo scm = new SecondCounterDemo(); JFrame f = new JFrame(); f.setcontentpane(scm); f.setsize(320, 200); f.setvisible(true); f.addwindowlistener(new WindowAdapter() public void windowclosing(windowevent e) System.exit(0); ); class SecondCounterRunnable extends JComponent implements Runnable private volatile boolean keeprunning; private Font paintfont = new Font("SansSerif", Font.BOLD, 14); private volatile String timemsg = "never started"; private volatile int arclen = 0; public SecondCounterRunnable() public void run() runclock(); public void runclock() DecimalFormat fmt = new DecimalFormat("0.000"); long normalsleeptime = 100;

144 int counter = 0; keeprunning = true; while (keeprunning) try Thread.sleep(normalSleepTime); catch (InterruptedException x) counter++; double countersecs = counter / 10.0; timemsg = fmt.format(countersecs); arclen = (((int) countersecs) % 60) * 360 / 60; repaint(); public void stopclock() keeprunning = false; public void paint(graphics g) g.setcolor(color.black); g.setfont(paintfont); g.drawstring(timemsg, 0, 15); g.filloval(0, 20, 100, 100); g.setcolor(color.white); g.filloval(3, 23, 94, 94); g.setcolor(color.red); g.fillarc(2, 22, 96, 96, 90, -arclen); 2. 생략 3. import java.awt.color; import java.awt.dimension; import java.awt.flowlayout; import java.awt.font; import java.awt.graphics; import java.awt.graphics2d; import java.awt.renderinghints; import java.awt.font.fontrendercontext; import java.awt.font.textlayout; import java.awt.geom.rectangle2d; import java.awt.image.bufferedimage; import javax.swing.jcomponent;

145 import javax.swing.jframe; import javax.swing.jpanel; public class ScrollText extends JComponent private BufferedImage image; private Dimension imagesize; private volatile int curroffset; private Thread internalthread; private volatile boolean nostoprequested; public ScrollText(String text) curroffset = 0; buildimage(text); setminimumsize(imagesize); setpreferredsize(imagesize); setmaximumsize(imagesize); setsize(imagesize); nostoprequested = true; Runnable r = new Runnable() public void run() try runwork(); catch (Exception x) x.printstacktrace(); ; internalthread = new Thread(r, "ScrollText"); internalthread.start(); private void buildimage(string text) RenderingHints renderhints = new RenderingHints( RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); renderhints.put(renderinghints.key_rendering, RenderingHints.VALUE_RENDER_QUALITY); BufferedImage scratchimage = new BufferedImage(1, 1, BufferedImage.TYPE_INT_RGB); Graphics2D scratchg2 = scratchimage.creategraphics(); scratchg2.setrenderinghints(renderhints); Font font = new Font("Serif", Font.BOLD Font.ITALIC, 24); FontRenderContext frc = scratchg2.getfontrendercontext(); TextLayout tl = new TextLayout(text, font, frc); Rectangle2D textbounds = tl.getbounds(); int textwidth = (int) Math.ceil(textBounds.getWidth());

146 int textheight = (int) Math.ceil(textBounds.getHeight()); int horizontalpad = 10; int verticalpad = 6; imagesize = new Dimension(textWidth + horizontalpad, textheight + verticalpad); image = new BufferedImage(imageSize.width, imagesize.height, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = image.creategraphics(); g2.setrenderinghints(renderhints); int baselineoffset = (verticalpad / 2) - ((int) textbounds.gety()); g2.setcolor(color.white); g2.fillrect(0, 0, imagesize.width, imagesize.height); g2.setcolor(color.blue); tl.draw(g2, 0, baselineoffset); scratchg2.dispose(); scratchimage.flush(); g2.dispose(); public void paint(graphics g) g.setclip(0, 0, imagesize.width, imagesize.height); int localoffset = curroffset; g.drawimage(image, -localoffset, 0, this); g.drawimage(image, imagesize.width - localoffset, 0, this); g.setcolor(color.black); g.drawrect(0, 0, imagesize.width - 1, imagesize.height - 1); private void runwork() while (nostoprequested) try Thread.sleep(100); curroffset = (curroffset + 1) % imagesize.width; repaint(); catch (InterruptedException x) Thread.currentThread().interrupt(); public void stoprequest() nostoprequested = false;

147 internalthread.interrupt(); public boolean isalive() return internalthread.isalive(); public static void main(string[] args) ScrollText st = new ScrollText(" 우리는스레드로애니메이션을할수있어요!"); JPanel p = new JPanel(new FlowLayout()); p.add(st); JFrame f = new JFrame("ScrollText Demo"); f.setcontentpane(p); f.setsize(400, 100); f.setvisible(true); 4. import java.awt.color; import java.awt.dimension; import java.awt.flowlayout; import java.awt.graphics; import java.awt.graphics2d; import java.awt.image; import java.awt.event.windowadapter; import java.awt.event.windowevent; import java.awt.geom.ellipse2d; import java.awt.geom.rectangle2d; import java.awt.image.bufferedimage; import javax.swing.jcomponent; import javax.swing.jframe; public class SwingWithThread extends JComponent private Image[] framelist; private long msperframe; private volatile int currframe; private Thread internalthread; private volatile boolean nostoprequested; public SwingWithThread(int width, int height, long mspercycle, int framespersec, Color fgcolor) setpreferredsize(new Dimension(width, height)); int framespercycle = (int) ((framespersec * mspercycle) / 1000);

148 msperframe = 1000L / framespersec; framelist = buildimages(width, height, fgcolor, framespercycle); currframe = 0; nostoprequested = true; Runnable r = new Runnable() public void run() try runwork(); catch (Exception x) // in case ANY exception slips through x.printstacktrace(); ; internalthread = new Thread(r); internalthread.start(); private Image[] buildimages(int width, int height, Color color, int count) BufferedImage[] im = new BufferedImage[count]; for (int i = 0; i < count; i++) im[i] = new BufferedImage(width, height, BufferedImage.TYPE_INT_ARGB); double xshape = ((double) (i * width)) / (double) count; ; double yshape = ((double) (i * height)) / (double) count; wshape, double wshape = 2.0 * (width - xshape); double hshape = 2.0 * (height - yshape); Rectangle2D shape = new Rectangle2D.Double(xShape, yshape, hshape); Graphics2D g2 = im[i].creategraphics(); g2.setcolor(color); g2.fill(shape); g2.dispose(); return im; private void runwork() while (nostoprequested) currframe = (currframe + 1) % framelist.length; repaint(); try

149 Thread.sleep(msPerFrame); catch (InterruptedException x) Thread.currentThread().interrupt(); public void stoprequest() nostoprequested = false; internalthread.interrupt(); public boolean isalive() return internalthread.isalive(); public void paint(graphics g) g.drawimage(framelist[currframe], 0, 0, this); public static void main(string[] args) SwingWithThread redsquish = new SwingWithThread(250, 200, 2500L, 10, Color.red); JFrame f = new JFrame(); f.setlayout(new FlowLayout()); f.add(redsquish); f.setsize(450, 250); f.setvisible(true); f.addwindowlistener(new WindowAdapter() public void windowclosing(windowevent e) System.exit(0); );