java program to build calculator

import java.util.Scanner;
public class Calculator{
  public static void main(String[] args){
     System.out.println("Enter integers x,y");
     Scanner in = new Scanner(System.in);
     int a,b;
     a = in.nextInt();
     b = in.nextInt();
     int r=0;
     System.out.println(" CALCULATOR ");
     r=a+b;
     System.out.println("a + b = "+r);

     r=a-b;
     System.out.println("a - b = "+r);

     r=a*b;
     System.out.println("a * b = "+r);

     r=a/b;
     System.out.println("a / b = "+r);
  }
}