명품 자바 에센셜 Chapter 2. 실습 문제

1.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("두 정수를 입력하세요>>");
		int a = scanner.nextInt();
		int b = scanner.nextInt();
		System.out.println(a + "+" + b + "은 " + (a + b));
	}
}

2.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("몇 층인지 입력하세요>>");
		int a = scanner.nextInt();
		System.out.println(a*5+"m 입니다.");
	}
}

3.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("x 값을 입력하세요>>");
		int x = scanner.nextInt();
		System.out.println("x="+x+", y="+(x*x-3*x+7)	);
	}
}

4.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("점 (x,y)의 좌표를 입력하세요>>");
		int x = scanner.nextInt();
		int y = scanner.nextInt();
		if ((x <= 100 && x >= 50) && (y <= 100 && y >= 50)) {
			System.out.println("점(" + x + "," + y + ")은 (50, 50)과 (100,100)의 사각형 내에 있습니다.");
		} else {
			System.out.println("점(" + x + "," + y + ")은 (50, 50)과 (100,100)의 사각형 내에 없습니다.");
		}
	}
}

5.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("논리 연산을 입력하요>>");
		boolean x = scanner.nextBoolean();
		String cac = scanner.next();
		boolean y = scanner.nextBoolean();

		switch (cac) {
		case "AND":
			if (x && y) {
				System.out.println("true");
			} else {
				System.out.println("false");
			}
			break;
		case "OR":
			if (x || y) {
				System.out.println("true");
			} else {
				System.out.println("false");
			}
			break;
		}
	}
}

6.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("돈의 액수를 입력하세요>>");
		int mon = scanner.nextInt();
		System.out.println("오만원" + (mon / 50000) + "개, 만원" + (mon % 50000 / 10000) + "개, 천원"
				+ (mon % 50000 % 10000 / 1000) + "개, 500원" + (mon % 50000 % 10000 % 1000 / 500) + "개, 100원"
				+ (mon % 50000 % 10000 % 1000 % 500 / 100) + "개, 10원" + (mon % 50000 % 10000 % 1000 % 500 % 100 / 10)
				+ "개, 1원" + (mon % 50000 % 10000 % 1000 % 500 % 100 % 10) + "개");
	}
}

7.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("돈의 액수를 입력하세요>>");
		int mon = scanner.nextInt();
		System.out.println("오만원" + (mon / 50000) + "개, 만원" + (mon % 50000 / 10000) + "개, 천원"
				+ (mon % 50000 % 10000 / 1000) + "개, 500원" + (mon % 50000 % 10000 % 1000 / 500) + "개, 100원"
				+ (mon % 50000 % 10000 % 1000 % 500 / 100) + "개, 10원" + (mon % 50000 % 10000 % 1000 % 500 % 100 / 10)
				+ "개, 1원" + (mon % 50000 % 10000 % 1000 % 500 % 100 % 10) + "개");
	}
}

8.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("커피 주문하세요>>");
		String cof = scanner.next();
		int amo = scanner.nextInt();

		switch (cof) {
		case "에스프레소":
			System.out.println(2000 * amo + "입니다.");
			break;
		case "아메리카노":
			System.out.println(2500 * amo + "입니다.");
			break;
		case "카푸치노":
			System.out.println(3000 * amo + "입니다.");
			break;
		case "카페라떼":
			System.out.println(3500 * amo + "입니다.");
			break;
		}
	}
}

9.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("1~99 사이의 정수를 입력하세요>>");

		int tsn = scanner.nextInt();

		if (tsn / 10 % 3 == 0) {
			if (tsn % 10 % 3 == 0) {
				System.out.println("박수짝짝");
			} else if (tsn % 3 == 0) {
				System.out.println("박수짝");
			} else {
				System.out.println("박수없음");
			}
		} else {
			System.out.println("박수없음");
		}
	}
}

10.

import java.util.Scanner;

public class RSP {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.println("커피 주문하세요>>");
		String cof = scanner.next();
		int amo = scanner.nextInt();

		switch (cof) {
		case "에스프레소":
			if (amo >= 10) {
				System.out.println(1900 * amo + "입니다");
			} else {

				System.out.println(2000 * amo + "입니다.");
			}
			break;
		case "아메리카노":
			System.out.println(2500 * amo + "입니다.");
			break;
		case "카푸치노":
			System.out.println(3000 * amo + "입니다.");
			break;
		case "카페라떼":
			System.out.println(3500 * amo + "입니다.");
			break;
		}
	}
}

Bonus 1.

import java.util.Scanner;

public class Arithmetic {
	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		System.out.print("식을 입력하세요>>");
		double op1 = scanner.nextDouble();
		String operator = scanner.next();
		double op2 = scanner.nextDouble();
		double result = 0;
		switch (operator) {
		case "+":
			result = op1 + op2;
			break;
		case "-":
			result = op1 - op2;
			break;
		case "*":
			result = op1 * op2;
			break;
		case "/":
			if (op2 == 0) {
				System.out.println("0으로 나눌 수 없습니다.");
				return;
			}
			result = op1 / op2;
			break;
		default:
			System.out.println("연산 기호가 잘못되었습니다.");
		}
		System.out.println("연산 결과 " + result);
	}
}