Why don't this return the "mrcf" value?

Question

m = int(input('Enter value of m : \t'))
n = int(input('Enter the value of n : \t'))
def GCD(m, n):
 for i in range(1,min(m,n)+1):
  if (m % i) == 0  and (n % i) == 0:
    mrcf = i
  return (mrcf)

This isn't returning anything. Why? - btb. I just started Py, and I'm already lovin this language :)

Answer 1

If I understand the intent of this function GCD, you're potentially updating mrcf multiple times, not just returning the first occurence of (m % i) == 0 and (n % i) == 0 :

m = int(input('Enter value of m : \t'))
n = int(input('Enter the value of n : \t'))

def GCD(m, n):
  for i in range(min(m,n), 1, -1):
    if (m % i) == 0  and (n % i) == 0:
      return i
  return 1

print(GCD(m, n))

UPDATE: as @Barmar suggested, reversing the loop is more efficient