이것이 자바다 | 4강_연습문제

4강 연습문제1

package chap04;

public class Exercise03{
	public static void main(String[] args) {
		int sum = 0;
		
		for (int i = 1; i <= 100; i++) {
			if ((i % 3) == 0)
				sum += i;
		}
		System.out.println("3의 배수의 합: " + sum);
	}
}

 

4강 연습문제2

package chap04;

public class Exercise04 {
	public static void main(String[] args) {
		int dot1, dot2;
		do {
		dot1 = (int)(Math.random()*5) + 1;
		dot2 = (int)(Math.random()*5) + 1;
		System.out.println("("+dot1+","+dot2+")");
		} while((dot1 + dot2) != 5);
	}
}

 

4강 연습문제3

package chap04;

public class Exercise05 {
	public static void main(String[] args) {
		for(int x = 1; x <= 10; x++) {
			for(int y = 1; y <= 10; y++) {
				if ((4*x + 5*y) == 60)
					System.out.println("("+x+","+y+")");
			}
		}
	}
}

 

4강 연습문제4

package chap04;

public class Exercise06 {
	public static void main(String args[]) {
		for(int i = 0; i < 5; i++) {
			for(int j = 0; j < i + 1; j++) {
				System.out.print('*');
			}
			System.out.println("");
		}
	}
}

 

4강 연습문제5

package chap04;

import java.util.Scanner;

public class Exercise07 {
	public static void main(String[] args) {
		boolean run = true;
		
		int balance = 0;
		
		Scanner scanner = new Scanner(System.in);
		
		while(run) {
			System.out.println("_______________________");
			System.out.println("1.예금 | 2.출금 | 3.잔고 | 4.종료");
			System.out.println("_______________________");
			System.out.print("선택> ");
			
			int menuNum = scanner.nextInt();
			switch(menuNum) {
				case 1:
					System.out.print("예금액>");;
					balance += scanner.nextInt();
					break;
				case 2:
					System.out.print("출금액>");
					balance -= scanner.nextInt();
					break;
				case 3:
					System.out.println("잔고>" + balance);
					break;
				case 4:
					run = false;
			}
		}
		System.out.println("프로그램 종료");
	}
}