I have started this program to calculate the greatest common divisor. This is what I have so far:

```
#include <iostream>
#include <math.h>
using namespace std;
int getGCD(int a, int b)
{
    a = a % b;
    if (a == 0)
    {
        return b;
        b = b % a;
    }
    if (b == 0)
    {
        return a;
    }
}
int main()

{
    int x, y;
    cout << "Please enter two integers x and y, for GCD calculation" << endl;
    cin >> x >> y;
    cout << "The GCD of " << x << "and " << y << " is" << getGCD(x, y) << endl;
    return 0;
}

```

I always get a 0 for the GCD. What am I doing wrong?