greatest common divisor

//while loop version
int gcd(int m, int n)
{
int r, q, d;
while (n!=0)
{
r = m % n;
q = m / n;
r = m - n * q;
m = n;
n = r;
}
return q;
}

//a recursive version, pretty, but maybe slower :)
int gcd(int m, int n)
{
if (!m || !n) return 0;
if (m < 0) return gcd(-m,n);
if (n < 0) return gcd(m,-n);
if (m < n) return gcd(n,m);
if (m%n) return gcd(n, m%n);
return n;
}