Determine the greatest common divisor (GCD) of two integers, m & n. The algorithm for GCD might be defined as follows:

While m is greater than zero:

If n is greater than m, swap m and n.

Subtract n from m.

n is the GCD

Code in C

int gcd(int m, int n)

/* The precondition are following: m>0 & n>0. Let g = gcd(m,n). */

{

while( m > 0 )

{

if( n > m )

{ int t = m; m = n; n = t; } /* swap m & n*/

/* m >= n > 0 */

m - = n;

}

return n;

}