#include<stdio.h>
#include<conio.h>
void main()
{
    int a,b;
    int op;
    //clrscr();
    printf(" 1.Addition\n 2.Subtraction\n 3.Multiplication\n 4.Division\n");
    printf("Enter the values of a & b: ");
    scanf("%d %d",&a,&b);
    printf("Enter your Choice : ");
    scanf("%d",&op);
    switch(op)
    {
    case 1	:
        printf("Sum of %d and %d is : %d",a,b,a+b);
        break;
    case 2	:
        printf("Difference of %d and %d is : %d",a,b,a-b);
        break;
    case 3	:
        printf("Multiplication of %d and %d is : %d",a,b,a*b);
        break;
    case 4	:
        printf("Division of Two Numbers is %d : ",a/b);
        break;
    default	:
        printf(" Enter Your Correct Choice.");
        break;
    }
    getch();
}

 OUTPUT:

 1.Addition
 2.Subtraction
 3.Multiplication
 4.Division
Enter the values of a & b:  20 15
Enter your Choice : 1
Sum of 20 and 15 is : 35