Simple calculation

Write a program to perform simple calculation using command line arguments.

#include<stdio.h>
#include<stdlib.h>
int main(int argc,char**argv)
{
	int x,y;
	int ans;
	if(argc != 4)
	{
		printf("Invalid Input\nUsage:./a.out operand1 operator operator 2\n");
		return 0;
	}
	x = atoi(argv[1]);
	y = atoi(argv[3]);
	switch(argv[2][0])
	{
		case '+':
		ans = x + y;
		printf("%d %c %d = %d\n",x,argv[2][0],y,ans);
		break;
		case '-':
		ans = x - y;
		printf("%d %c %d = %d\n",x,argv[2][0],y,ans);
		break;
		case '*':
		ans = x * y;
		printf("%d %c %d = %d\n",x,argv[2][0],y,ans);
		break;
		case '/':
		ans = x / y;
		printf("%d %c %d = %d\n",x,argv[2][0],y,ans);
		break;
		case '%':
		ans = x % y;
		printf("%d %c %d = %d\n",x,argv[2][0],y,ans);
		break;
		default:
		printf("Invalid choice\n");
	}
	return 0;
}

Output

./a.out 5 + 7
5 + 7 = 12

./a.out 5 '*' 9
5 * 9 = 45