명품 자바 프로그래밍 2장 실습 문제

✏️ 2장 실습문제 - 1번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("원화를 입력하세요(단위 원)>>");
        int money = scanner.nextInt();
        double res = ((double)money)/1100;
        System.out.println(money+"원은 $"+res+"입니다.");
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 2번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("2자리수 정수 입력(10~99)>>");
        int num1 = scanner.nextInt();
        if((num1/10)==(num1%10)){
            System.out.println("Yes! 10의 자리와 1의 자리가 같습니다.");
        }
        else
            System.out.println("No! 10의 자리와 1의 자리가 다릅니다");
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 3번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("금액을 입력하시오>>");
        int money = scanner.nextInt();
        if(money>=50000) {
            System.out.println("오만원권 " + money / 50000 + "매");
            money%=50000;
        }
        if(money>=10000){
            System.out.println("만원권 " + money / 10000 + "매");
            money%=10000;
        }
        if(money>=1000){
            System.out.println("천원권 " + money / 1000 + "매");
            money%=1000;
        }
        if(money>=100){
            System.out.println("백원 " + money / 100 + "개");
            money%=100;
        }
        if(money>=50){
            System.out.println("오십원 " + money / 50 + "개");
            money%=50;
        }
        if(money>=10){
            System.out.println("십원 " + money / 10 + "개");
            money%=10;
        }
        if(money>=1){
            System.out.println("일원 " + money / 1 + "개");
        }
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 4번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("정수 3개 입력>>");
        int num1 = scanner.nextInt();
        int num2 = scanner.nextInt();
        int num3 = scanner.nextInt();
        if(num1>num2 && num2>num3)
            System.out.print("중간 값은 "+num2);
        else if(num2>num3 && num3>num1)
            System.out.print("중간 값은"+num3);
        else
            System.out.print("중간 값은"+num1);
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 5번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("정수 3개 입력>>");
        int num1 = scanner.nextInt();
        int num2 = scanner.nextInt();
        int num3 = scanner.nextInt();
        if(num1+num2>num3 && num2+num3>num1 && num1+num3>num2)
            System.out.println("삼각형이 됩니다");
        else
            System.out.println("삼각형이 만들어지지 않습니다");
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 6번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("1~99 사이의 정수를 입력하시오>>");
        int num1 = scanner.nextInt();
        if(num1/10 == 3 || num1/10==6 || num1/10==9){
            if(num1%10 == 3 || num1 %10==6 || num1%10==9){
                System.out.println("박수짝짝");
            }
            else
                System.out.println("박수짝");
        }
        else if(num1%10 == 3 || num1%10==6 || num1%10==9){
            if(num1/10 == 3 || num1 /10==6 || num1/10==9){
                System.out.println("박수짝짝");
            }
            else
                System.out.println("박수짝");
        }
        else
            System.out.println();
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 7번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
       Scanner scanner = new Scanner(System.in);
        System.out.print("1~99 사이의 정수를 입력하시오>>");
        int num1 = scanner.nextInt();
        int num2 = scanner.nextInt();

        if(num1>=100 && num1<=200 && num2>=100&&num2<=200)
            System.out.println("("+num1+","+num2+")는 사각형 안에 있습니다.");
        else
            System.out.println("("+num1+","+num2+")는 사각형 안에 없습니다.");
        scanner.close();
    }
}

 

✏️ 2장 실습문제 - 8번

package ex;
import java.util.*;
public class SolveProblem {
    public static boolean inRect(int x, int y, int rectx1, int rectx2, int recty1, int recty2) {
        if ((x >= rectx1 && x <= rectx2) && (y >= recty1 && y <= recty2))
            return true;
        else
            return false;
    }

    public static void main(String[] args) {
        System.out.println("두 점 (x1,y1), (x2,y2)의 좌표를 입력하시오 >>");
        Scanner s = new Scanner(System.in);
        int x1 = s.nextInt();
        int y1 = s.nextInt();
        int x2 = s.nextInt();
        int y2 = s.nextInt();

        if (inRect(x1, y1, 100, 100, 200, 200) ||
                inRect(x2, y2, 100, 100, 200, 200) ||
                inRect(x1, y2, 100, 100, 200, 200) ||
                inRect(x2, y1, 100, 100, 200, 200))
            System.out.println("사각형이 겹칩니다.");
        else if ((inRect(x1, y1, 100, 100, 200, 200)) &&
                inRect(x2, y2, 100, 100, 200, 200) &&
                inRect(x2, y1, 100, 100, 200, 200) &&
                inRect(x1, y2, 100, 100, 200, 200))
            System.out.println("사각형이 겹칩니다.");
        else if ((inRect(100, 100, x1, y1, x2, y2)) &&
                inRect(100, 200, x1, y1, x2, y2) &&
                inRect(200, 100, x1, y1, x2, y2) &&
                inRect(200, 200, x1, y1, x2, y2))
            System.out.println("사각형이 겹칩니다.");
        else
            System.out.println("사각형이 겹치지 않습니다.");
        s.close();
    }
}

 

✏️ 2장 실습문제 - 9번

package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("원의 중심과 반지를 입력>>");
        double a = scanner.nextDouble();
        double b = scanner.nextDouble();
        double r = scanner.nextDouble();

        System.out.print("점 입력>>");
        double x = scanner.nextDouble();
        double y = scanner.nextDouble();

        if(x>=a-r&&x<=a+r&&y>=b-r&&y<=b+r)
            System.out.println("점 ("+x+","+y+")는 원 안에 있다.");
        else
            System.out.println("점 ("+x+","+y+")는 원 안에 없다.");
        scanner.close();
    }

}

 

✏️ 2장 실습문제 - 10번

package ex;
import java.util.*;

public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("첫번째 원의 중심과 반지름 입력");
        int a = scanner.nextInt();
        int b = scanner.nextInt();
        double r1 = scanner.nextDouble();

        System.out.println("두번째 원의 중심과 반지름 입력");
        int a2 = scanner.nextInt();
        int b2 = scanner.nextInt();
        double r2 = scanner.nextDouble();
        double distance = 0;

        distance = Math.sqrt((a-a2)*(a-a2)+(b-b2)*(b-b2));
        if(distance<=r1+r2)
            System.out.println("두 원은 서로 겹친다");
        else
            System.out.println("두 원은 서로 겹치지 않는다");
    }
}

 

✏️ 2장 실습문제 - 11번

// 11 - 1
package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("달을 입력하세요(1~12)>>");
        int month = scanner.nextInt();
        if(month>=3&&month<=5)
            System.out.println("봄");
        else if(month>=6&&month<=8)
            System.out.println("여름");
        else if(month>=9&&month<=11)
            System.out.println("가을");
        else if(month==12 || month ==1 || month ==2)
            System.out.println("겨울");
        else
            System.out.println("잘못 입력");
    }
}

// 11 - 2
package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("달을 입력하세요(1~12)>>");
        int month = scanner.nextInt();
        switch (month) {
            case 3: case 4: case 5:
                System.out.println("봄");
                break;
            case 6:case  7: case 8:
                System.out.println("여름");
                break;
            case 9: case 10: case 11:
                System.out.println("가을");
                break;
            case 12: case 1: case 2:
                System.out.println("겨울");
                break;
            default:
                System.out.println("잘못 입력");
                break;
        }
    }
}

 

✏️ 2장 실습문제 - 12번

// 12-1
package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("연산>>");
        int n1 = scanner.nextInt();
        String op = scanner.next();
        int n2 = scanner.nextInt();
        if(op.equals("+"))
            System.out.println(n1+"+"+n2+"의 결과는 " +(n1+n2));
        else if(op.equals("-"))
            System.out.println(n1+"-"+n2+"의 결과는 " +(n1-n2));
        else if(op.equals("*"))
            System.out.println(n1+"*"+n2+"의 결과는 " +(n1*n2));
        else {
            if (n2 != 0)
                System.out.println(n1 + "/" + n2 + "의 결과는 " + (n1 / n2));
            else
                System.out.println("계산 불가능");
        }
        scanner.close();
    }
}

//12-2
package ex;
import java.util.*;
public class SolveProblem {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("연산>>");
        int n1 = scanner.nextInt();
        String op = scanner.next();
        int n2 = scanner.nextInt();
        switch (op) {
            case "+":
                System.out.println(n1 + "+" + n2 + "의 결과는 " + (n1 + n2));
                break;
            case "-":
                System.out.println(n1 + "-" + n2 + "의 결과는 " + (n1 - n2));
                break;
            case "*" :
                System.out.println(n1 + "*" + n2 + "의 결과는 " + (n1 * n2));
                break;
            case "/" :
                if(n2!=0)
                    System.out.println(n1 + "/" + n2 + "의 결과는 " + (n1 / n2));
                else
                    System.out.println("계산 불가능");
                break;
        }
        scanner.close();
    }

}