1. 자바 사칙연산 계산기

import java.util.Scanner;
 
public class Day1_1 {
 
  public static void main(String[] args) {
 
   
 
   Scanner sc;
 
   sc = new Scanner(System.in);
 
   
 
   int sum = 0;
 
   int num = sc.nextInt();
 
   System.out.println("1.덧셈 2.뺄셈 3.곱셈 4.나눗셈");
 
   int d= sc.nextInt();
 
   int num2 = sc.nextInt();
 
   
 
   
 
   switch(d)
 
   {
 
   case 1:
 
    sum = num+num2;
 
    System.out.println(sum);
 
    break;
 
   case 2:
 
    sum = num-num2;
 
    System.out.println(sum);
 
    break;
 
   case 3:
 
    sum = num*num2;
 
    System.out.println(sum);
 
    break;
 
   case 4:
 
    sum = num/num2;
 
    System.out.println(sum);
 
    break;
 
   default:
 
    System.out.println("잘못입력하였습니다");
 
    break;
 
   }
 
  } 
 
}