GCD computing without modulo neither division ops

gcd_limited_ops.py

# computes the greatest common divisor
# with a small subset of math operations
# that does not include `division` or `modulo` 
def gcd(a, b):
	while b>0:	
		c = a
		a = b
		while(c >= b):
			c -= b
		b = c
	return a

if __name__ == '__main__':
	from fractions import gcd as gcd_

	for i in xrange(20):
		print gcd(13, i), gcd_(13, i)
		print gcd(20, i), _(20, i)