Greatest Common Divisor

The greatest common divisor (GCD) of two values can be computed using Euclid's algorithm. Starting with the values m and n, we recursively apply the formula: n, m = m, n%m until m is 0. At that point, n is the GCD of the original m and n. Write a function that finds the GCD of two numbers using this algorithm.

Test your function with the following main() program:


int main()
{
    int n, m;
    cout << "Please input two positive numbers -- ";
    cin >> n >> m;
    cout << endl;
    printf("GCD(%d,%d) = %d\n", n, m, gcd(n,m) );
    return 0;
}

The program may run as follows.


Please input two positive numbers -- 33 90

GCD(33,90) = 3