Python 3函数返回None。 GCD和Euclid

Question

这个python 3代码在我显然应该返回12时返回None。我无法弄明白。

from math import *

def gcd(m,n):

    print("gcd: ",m,", ",n,")")

    if n == 0:
        print(m)
        return m
    else:
        gcd(n,m//n)

def main():

    m = 60
    n = 24
    result = gcd(m,n)
    print(result)

main()

Answer 1

更改行

gcd(n,m//n)

到

return gcd(n,m//n)