[完][명품 JAVA ESSENTIAL] CH2 실습문제

 

"개정판: 명품 JAVAESSENTIAL(황기태)"교재에 수록된 문제들을 풀어서 올립니다. 문제의 번호만 표기하고 답안만 적는 형태로 업로드 하고있습니다. 개인 풀이이므로 오답이 있을 수 있으며 오답 발견 시 댓글 남겨주시면 감사하겠습니다😊 - #이 표시된 건 아직 풀지 못한 문제 or 헷갈리는 문제입니다! 추후에 다시 풀어서 올릴 예정이에요! -ujeyhx-

 

🔎실습문제

 

 

1)

import java.util.Scanner;

public class TEST {

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

 

 

---

2)

import java.util.Scanner;

public class TEST {

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

 

---

3)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int x,y;
		System.out.print("X 값을 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		x = sc.nextInt();
		y = (int) (Math.pow(x,2)-3*x+7);
		System.out.println("x="+ x +","+" y="+ y);
		sc.close();
	}
	
}

 

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4)

import java.util.Scanner;

public class TEST {

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

 

---

5)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
	
		
		System.out.print("논리 연산을 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		boolean a = sc.nextBoolean();
		String op = sc.next();
		boolean b = sc.nextBoolean();
		
		switch(op){
			case "AND" :
				if (a && b)
				System.out.println("true");
				else
				System.out.println("false");
				break;
				
			case "OR" :
				if (a || b)
				System.out.println("true");
				else
				System.out.println("false");
				break;
				
			default:
				System.out.println("잘못입력");
		}
		sc.close();
	}
}

---

6)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int money;
		int m50000,m10000,m1000,m500,m100,m10,m1;
		System.out.print("돈의 액수를 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		money = sc.nextInt();
		
		m50000=money/50000;
		m10000=(money%50000)/10000;
		m1000=(money%50000%10000)/1000;
		m500=(money%50000%10000%1000)/500;
		m100=(money%50000%10000%1000%500)/100;
		m10=(money%50000%10000%1000%500%100)/10;
		m1=(money%50000%10000%1000%500%100%10);
		
		System.out.print("오만원"+m50000+"개 ");
		System.out.print("만원"+m10000+"개 ");
		System.out.print("천원"+m1000+"개 ");
		System.out.print("500원"+m500+"개 ");
		System.out.print("100원"+m100+"개 ");
		System.out.print("10원"+m10+"개 ");
		System.out.print("1원"+m1+"개 ");
		
		sc.close();
	}
}

 

---

7)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		String grade;
		System.out.print("학점을 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		grade = sc.next();
		
		switch (grade) {
		case "A": case "B":
			System.out.print("Excellent");
			break;
		case "C": case "D":
			System.out.print("Good");
			break;
		case "F":
			System.out.print("Bye");
			break;
		default :
			System.out.print("잘못입력하셨습니다.");
		}
		sc.close();
	}
}

 

 

---

8)

//FOR 문

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int price = 0;
		System.out.print("커피 주문하세요>>");
		Scanner sc = new Scanner(System.in);
		String coffee = sc.next();
		int num = sc.nextInt();
		
		if (coffee.equals("카푸치노"))
			price = 3000;
		else if (coffee.equals("아메리카노"))
			price = 2500;
		else if (coffee.equals("에스프레소"))
			price = 2000;
		else if (coffee.equals("카페라떼"))
			price = 3500;

		System.out.print((price*num) +"원입니다.");
		
		sc.close();
		
	}
}

 

//SWITCH 문
import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int price = 0;
		System.out.print("커피 주문하세요>>");
		Scanner sc = new Scanner(System.in);
		String coffee = sc.next();
		int num = sc.nextInt();
		
		switch (coffee) {
		case "카푸치노":
			price = 3000;
			break;
		case "아메리카노":
			price = 2500;
			break;
		case "에스프레소":
			price = 2000;
			break;
		case "카페라떼":
			price = 3500;
			break;
		}
		
		System.out.print((price*num) +"원입니다.");
		
		sc.close();
		
	}
}

 

---

9)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int num;
		System.out.print("1~99 사이의 정수를 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		num = sc.nextInt();
		
		int first = num/10;
		int second = num%10;
		int clap = 0;
		
		if (first != 0 && first % 3 == 0)
			clap ++;
		if (second != 0 && second % 3 == 0)
			clap ++;
		
		
		if (clap == 0)
				System.out.print("박수 없음");
		else if (clap == 1)
				System.out.print("박수 짝");
		else if (clap == 2)
				System.out.print("박수 짝짝");
                
       sc.close();
	}
}

 

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int num;
		System.out.print("1~99 사이의 정수를 입력하세요>>");
		Scanner sc = new Scanner(System.in);
		num = sc.nextInt();
		
		int first = num/10;
		int second = num%10;
		
		if (first == 3 && first == 6 && first == 9 )
			System.out.print("박수 짝");
		else
		if (second == 3 && second == 6 && second == 9)
			System.out.print("박수 짝짝");
		else
			System.out.print("박수 없음.");
		
	
		sc.close();
	}
}

---

10)

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		
		int price = 0;
		System.out.print("커피 주문하세요>>");
		Scanner sc = new Scanner(System.in);
		String coffee = sc.next();
		int num = sc.nextInt();
		double priceSum = 0;
		
		switch (coffee) {
		case "카푸치노":
			price = 3000;
			break;
		case "아메리카노":
			price = 2500;
			break;
		case "에스프레소":
			price = 2000;
			break;
		case "카페라떼":
			price = 3500;
			break;
		}
		
		priceSum = (price*num);
		
		if (coffee.equals("에스프레소")) {
			if (num>=10)
					priceSum -= ((double) (price*num)) * 0.05;
		}

		
		System.out.print((int)priceSum +"원입니다.");
		
		sc.close();
		
	}
}

 

 

 

---

Bonus 1 )

 

 

import java.util.Scanner;

public class TEST {

	public static void main(String[] args) {
		

		
		Scanner sc = new Scanner(System.in);
		System.out.print("식을 입력하세요>>");
		double op1 = sc.nextDouble(); 
		String op = sc.next();
		double op2 = sc.nextDouble();
		double result = 0;
		
		
		switch (op) {
		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(result);
	
		sc.close();
		
	}
}