Python 3函数返回None.GCD和欧几里得

Question

这个python 3代码对我来说返回None，而它显然应该返回12。我想不通。

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)

至

return gcd(n,m//n)