[JAVA] 백준 단계별로 문제풀기 - 1단계 입출력과 사칙연산

1 - 1. Hello World 출력하기

public class Main {
    public static void main(String arg[]) {
        System.out.println("Hello World!");
    }
}

 

1 - 2. We love kriii

public class Main {
    public static void main(String arg[]) {
        System.out.println("강한친구 대한육군");
        System.out.println("강한친구 대한육군");
    }
}

 

1 - 3. 고양이

• \는 앞에 \를 입력해야지 출력이 됩니다.
• \n은 줄 바꿈입니다.

public class Main {
    public static void main(String arg[]) {
        System.out.println( "\\    /\\\n" + 
			" )  ( ')\n" + 
			"(  /  )\n" + 
			" \\(__)|");
    }
}

 

1 - 4. 개

• "도 앞에 \를 넣어야지 출력이 됩니다.

public class Main {
    public static void main(String arg[]) {
        System.out.println("|\\_/|\n"
            + "|q p|   /}\n"
            + "( 0 )\"\"\"\\\n"
            + "|\"^\"`    |\n"
            + "||_/=\\\\__|");
    }
}

 

1 - 5. A + B

• 자바에서 입력을 받기 위해서는 Scanner클래스를 import 해줘야 합니다.
• String으로 입력받을 때는 next()나 nextLine()으로, Int를 입력받을 때는 nextInt()를 사용하여 입력받습니다.

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        int x;
        int y;
        
        Scanner sc = new Scanner(System.in);
        
        x = sc.nextInt();
        y = sc.nextInt();
        
        System.out.println(x+y);
    }
}

 

1 - 6. A - B

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        int x;
        int y;
        
        Scanner sc = new Scanner(System.in);
        
        x = sc.nextInt();
        y = sc.nextInt();
        
        System.out.println(x-y);
    }
}

 

1 - 7. A * B

import java.util.Scanner;

public class Main {
    public static void main(String arg[]) {
        int x;
        int y;
        
        Scanner sc = new Scanner(System.in);
        x = sc.nextInt();
        y = sc.nextInt();
        
        System.out.println(x*y);
    }
}

 

1 - 8. A / B (A > 0, B < 10)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        double x;
        double y;
        
        Scanner sc = new Scanner(System.in);
        
        x = sc.nextDouble();
        y = sc.nextDouble();
        
        if(x > 0 || y < 10) {
             System.out.println(x/y);   
        }
    } 
}

 

1 - 9. 사칙연산 (1 ≤ A, B ≤ 10,000)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int x;
        int y;
        
        Scanner sc = new Scanner(System.in);
        
        x = sc.nextInt();
        y = sc.nextInt();
        
        if(x >= 1 || y <= 10000) {
             System.out.println(x+y);
            System.out.println(x-y);
            System.out.println(x*y);
            System.out.println(x/y);
            System.out.println(x%y);   
        }
    }
}

 

1 - 10. ??!

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        String id;
        
        Scanner sc = new Scanner(System.in);
        
        id = sc.next();
        
        System.out.println(id + "??!");
    }
}

 

1 - 11. 1998년생인 내가 태국에서는 2541년생?! (1000 ≤ y ≤ 3000)

• 불기 연도 -> 서기연도

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        int y;
        
        Scanner sc = new Scanner(System.in);
        
        y = sc.nextInt();
        
        if(y >= 1000 || y <= 3000) {
            System.out.println(y - 543);
        }
    }
}

 

1 - 12. 나머지

• (A+B)%C는 ((A%C) + (B%C))%C 와 같을까?
• (A×B)%C는 ((A%C) × (B%C))%C 와 같을까?

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
        int x;
        int y;
        int z;
        
        Scanner sc = new Scanner(System.in);
        
        x = sc.nextInt();
        y = sc.nextInt();
        z = sc.nextInt();
        
        if(x >= 2 || z <= 10000) {
            System.out.println((x+y)%z);
            System.out.println(((x%z)+(y%z))%z);
            System.out.println((x*y)%z);
            System.out.println(((x%z)*(y%z))%z);   
        }
    }
}

 

1 - 12. 곱셈

import java.util.Scanner;

public class Main {
    public static void main(String args[]) {
         int x;
        int y;
        int y1;
        int y2;
        int y3;
    
        Scanner sc = new Scanner(System.in);
    
        x = sc.nextInt();
        y = sc.nextInt();
    
        y1 = y / 100;
        y2 = (y % 100) / 10;
        y3 = ((y % 100) % 10);
    
        System.out.println(x * y3);
        System.out.println(x * y2);
        System.out.println(x * y1);   
        System.out.println(x*y3 + x*y2*10 + x*y1*100);
    }
}