C program to calculate the GCD of two numbers using recursive functions

#include <stdio.h>
int GCD(int, int);
int main()
{
int num1, num2, res;
printf("\n Enter the two numbers: ");
scanf("%d %d", &num1, &num2);
res = GCD(num1, num2);
printf("\n GCD of %d and %d = %d", num1, num2, res);
return 0;
}
int GCD(int x, int y)
{
int rem;
rem = x%y;
if(rem==0)
 return y;
else
 return (GCD(y, rem));
}