명품 자바 프로그래밍 6장 실습 문제

✏️  6장 실습문제 - 1

package ex;
import java.util.*;

class MyPoint{
    private int x,y;

    public MyPoint(int x, int y) {
        this.x = x;
        this.y = y;
    }

    public boolean equals(MyPoint p) {
        if(this.x==p.x && this.y==p.y)
            return true;
        else
            return false;
    }
    public String toString(){
        String str = "point("+this.x+","+this.y+")";
        return str;
    }
}
public class SolveProblem{
    public static void main(String[] args) {
        MyPoint p = new MyPoint(3,50);
        MyPoint q = new MyPoint(4,50);
        System.out.println(p);
        if(p.equals(q))
            System.out.println("같은 점");
        else
            System.out.println("다른 점");
    }
}

 

✏️  6장 실습문제 - 2

package ex;
import java.util.*;

class Circle{
    private int x,y,r;

    public Circle(int x, int y, int r) {
        this.x = x;
        this.y = y;
        this.r = r;
    }
    public boolean equals(Circle c){
        if(this.x==c.x&&this.y==c.y)
            return true;
        else
            return false;
    }
    public String toString(){
        String str = "Circle("+this.x+","+this.y+")반지름"+this.r;
        return str;
    }
}

public class SolveProblem{
    public static void main(String[] args) {
        Circle a = new Circle(2,3,5);
        Circle b = new Circle(2,3,30);
        System.out.println("원 a : "+a);
        System.out.println("원 b : "+b);
        if(a.equals(b))
            System.out.println("같은 원");
        else
            System.out.println("다른 원");
    }
}

 

✏️  6장 실습문제 - 3

// main 패키지
package ex;
import etc.Calc;
import java.util.*;

public class SolveProblem{
    public static void main(String[] args) {
        Calc c = new Calc(10,20);
        System.out.println(c.sum());
    }
}

// etc 패키지
package etc;

public class Calc {
    private int x,y;

    public Calc(int x, int y) {
        this.x = x;
        this.y = y;
    }
    public int sum(){
        return x+y;
    }
}

 

 

✏️  6장 실습문제 - 4

// Circle 클래스
package derived;
import base.Shape;
public class Circle extends Shape{
    public void draw(){
        System.out.println("Circle");
    }
}

// Shape 클래스
package base;
public class Shape {
    public void draw(){
        System.out.println("Shape");
    }
}

// GraphicEditor 클래스
package app;
import base.Shape;
import derived.Circle;
public class GraphicEditor {
    public static void main(String[] args) {
        Shape shape = new Circle();
        shape.draw();
    }
}

 

✏️  6장 실습문제 - 5

package ex;
import java.util.*;

public class SolveProblem{
    public static void main(String[] args) {
        Calendar calendar = Calendar.getInstance();
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        int min = calendar.get(Calendar.MINUTE);

        System.out.println("현재 시간은 "+hour+"시 "+min+"분입니다.");
        if(hour>4 && hour<12)
            System.out.println("Good Morning");
        else if(hour<18&&hour>=12)
            System.out.println("Good Afternoon");
        else if(hour>=18&&hour<22)
            System.out.println("Good Evening");
        else
            System.out.println("Good night");
    }
}

 

✏️  6장 실습문제 - 6

import java.util.Calendar;
import java.util.Scanner;

class Player {
	Calendar now = Calendar.getInstance();
	Scanner sc = new Scanner(System.in);
	private String name;
	private int sec1, sec2;
	
	public Player(String name) {	
		this.name = name;
	}
	
	public int run() {	
		System.out.print(name + "시작 <Enter>키>>");
		sec1 = enter();
		System.out.print("10초 예상 후 <Enter>키>>");
		sec2 = enter();
		
		if(sec1 >= sec2)
			return (sec2 + 60) - sec1;
		else return sec2 - sec1;
	}
	
	public int enter() {	
		sc.nextLine();
		now = Calendar.getInstance();
		System.out.println("현재 초 시간 = " + now.get(Calendar.SECOND));
		return now.get(Calendar.SECOND);
	}
}

public class Prac06 {
	public static void main(String[] args) {
		Player player1 = new Player("황기태");
		Player player2 = new Player("이재문");
		
		System.out.println("10초에 가까운 사람이 이기는 게임입니다.");
		int resultP1 = player1.run();
		int resultP2 = player2.run();
		
		if(Math.abs(resultP1 - 10) < Math.abs(resultP2 - 10))
			System.out.println("황기태의 결과 " + resultP1 + ", 이재문의 결과 " + resultP2 + ", 승자는 황기태");
		else 
			System.out.println("황기태의 결과 " + resultP1 + ", 이재문의 결과 " + resultP2 + ", 승자는 이재문");
			
		

	}
}

 

✏️  6장 실습문제 - 7

// 1번
package ex;
import java.util.*;

public class SolveProblem{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(true){
            System.out.print(">>");
            String str = scanner.nextLine();
            if(str.equals("그만")){
                System.out.println("종료합니다...");
                break;
            }
            StringTokenizer stringTokenizer = new StringTokenizer(str," ");
            System.out.println("어절 개수는 "+stringTokenizer.countTokens());
        }
        scanner.close();
    }
}

// 2번
package ex;
import java.util.*;

public class SolveProblem{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(true){
            System.out.print(">>");
            String str = scanner.nextLine();
            if(str.equals("그만")){
                System.out.println("종료합니다...");
                break;
            }
            String [] s =str.split(" ");
            System.out.println("어절 개수는 "+s.length);
        }
        scanner.close();
    }
}

 

✏️  6장 실습문제 - 8

package ex;
import java.util.*;

public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("문자열을 입력하세요. 빈칸이 있어도 되고 영어 한글 모두 됩니다.");
        String str = scanner.nextLine();
        for(int i=1;i<str.length()+1;i++){
            System.out.print(str.substring(i));
            for(int j=0;j<i;j++){
                System.out.print(str.charAt(j));
            }
            System.out.println();
        }
        scanner.close();
    }
}

 

✏️  6장 실습문제 - 9

package ex;
import java.util.*;
class Player {
    private String name;

    Player(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public int select() {
        Scanner sc = new Scanner(System.in);
        System.out.print("철수[가위(1), 바위(2), 보(3), 끝내기(4)]>>");
        return sc.nextInt();
    }
}

class Computer extends Player {
    public Computer(String name) {
        super(name);
    }

    public int select() {
        return (int)(Math.random() * 3 + 1);
    }
}

class Game {
    private String[] game = {"가위", "바위", "보"};
    Player[] player = new Player[2];

    public Game() {
        player[0] = new Player("철수");
        player[1] = new Computer("컴퓨터");
    }

    public void run() {
        int playerNum, computerNum;

        while(true) {
            playerNum = player[0].select();
            if(playerNum < 1 || playerNum > 4)
                System.out.println("잘못 입력했습니다.");
            else if(playerNum == 4)
                break;

            computerNum = player[1].select();

            System.out.print(player[0].getName() + "(" + game[playerNum - 1] + ")  :  ");
            System.out.println(player[1].getName() + "(" + game[computerNum - 1] + ")");

            if(playerNum == computerNum)
                System.out.println("비겼습니다.");
            else if((playerNum == 1 && computerNum == 2) || (playerNum == 2 && computerNum == 3) || (playerNum == 3 && computerNum == 1))
                System.out.println(player[1].getName() + "가 이겼습니다.");
            else if((playerNum == 1 && computerNum == 3) || (playerNum == 2 && computerNum == 1) || (playerNum == 3 && computerNum == 2))
                System.out.println(player[0].getName() + "가 이겼습니다.");
        }
    }
}

public class Prac09 {
    public static void main(String[] args) {
        Game game = new Game();
        game.run();
    }
}

 

✏️  6장 실습문제 - 10

package ex;
import java.util.*;

class Person{
    private String name;
    private Scanner sc;
    private int[] arr;

    public Person(String name) {
        this.name = name;
        sc = new Scanner(System.in);
        arr = new int[3];
    }

    public String getName() {
        return name;
    }
    public boolean run(){
        System.out.print("["+this.name+"]:<Enter>");
        boolean check = enter();
        for(int i=0;i<arr.length;i++){
            System.out.print(arr[i]+"\t");
            arr[i]=0;
        }
        if(check)
            return true;
        else {
            System.out.println("아쉽군요!");
            return false;
        }
    }
    public boolean enter(){
        String s = sc.nextLine();
        for(int i=0;i<arr.length;i++){
            int n = (int)(Math.random()*3+1);
            arr[i]=n;
        }
        if(arr[0]==arr[1]&&arr[1]==arr[2])
            return true;
        else {
            return false;
        }
    }
}
public class SolveProblem{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("1번째 선수 이름>>");
        String player1 = scanner.nextLine();
        System.out.print("2번째 선수 이름>>");
        String player2 = scanner.nextLine();
        Person p1 = new Person(player1);
        Person p2 = new Person(player2);
        while(true){
            boolean check = p1.run();
            if(check){
                System.out.println(p1.getName()+"님이 이겼습니다!");
                break;
            }
            boolean check2 = p2.run();
            if(check2){
                System.out.println(p2.getName()+"님이 이겼습니다!");
                break;
            }
        }
    }
}

 

✏️  6장 실습문제 - 11

package ex;
import java.util.*;

public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print(">>");
        String str = scanner.nextLine();
        StringBuffer stringBuffer = new StringBuffer(str);
        while (true) {
            System.out.print("명령: ");
            String s = scanner.nextLine();
            if (s.equals("그만")) {
                System.out.println("종료합니다!");
                break;
            }

            String[] tokens = s.split("!");
            if (tokens.length != 2) {
                System.out.println("잘못된 입력입니다");
                continue;
            } else {
                if (tokens[0].length() == 0 || tokens[1].length() == 0) {
                    System.out.println("잘못된 명령입니다!");
                    continue;
                }
                int index = stringBuffer.indexOf(tokens[0]);
                System.out.println(index);
                if(index==-1){
                    System.out.println("잘못된 명령입니다!");
                    continue;
                }
                stringBuffer.replace(index,index+tokens[0].length(),tokens[1]);
                System.out.println(stringBuffer.toString());
            }
        }
    }
}

 

✏️  6장 실습문제 - 12

package ex;
import java.util.*;

class Person{
    private String name;
    private Scanner sc;
    private int[] arr;

    public Person(String name) {
        this.name = name;
        sc = new Scanner(System.in);
        arr = new int[3];
    }

    public String getName() {
        return name;
    }
    public boolean run(){
        System.out.print("["+this.name+"]:<Enter>");
        boolean check = enter();
        for(int i=0;i<arr.length;i++){
            System.out.print(arr[i]+"\t");
            arr[i]=0;
        }
        if(check)
            return true;
        else {
            System.out.println("아쉽군요!");
            return false;
        }
    }
    public boolean enter(){
        String s = sc.nextLine();
        for(int i=0;i<arr.length;i++){
            int n = (int)(Math.random()*3+1);
            arr[i]=n;
        }
        if(arr[0]==arr[1]&&arr[1]==arr[2])
            return true;
        else {
            return false;
        }
    }
}
public class SolveProblem{
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("겜블링 게임에 참여할 선수 숫자>>");
        int size = scanner.nextInt();
        Person [] p = new Person[size];
        for(int i=0;i<p.length;i++){
            System.out.print(i+1+"번째 선수 이름>>");
            String player = scanner.next();
            p[i]=new Person(player);
        }
        while(true){
            boolean isFinsih = false;
            for(int i=0;i<p.length;i++){
                boolean check = p[i].run();
                if(check){
                    System.out.println(p[i].getName()+"님이 이겼습니다!");
                    isFinsih=true;
                    break;
                }
            }
            if(isFinsih)
                break;
        }
    }
}