Euclid算法的python代码中的奇怪错误

Question

I'm trying to write a simple python code that computes the greatest common divisor of two integers.

def gcd(a,b):
  if (b==0):
    return a
  gcd(b,a%b)

This simple code uses the Euclid's algorithm . The problem is that it doesn't return except when b is zero . what is the source of this bug ?

Answer 1

Add return in recursive call as well.

def gcd(a,b):
  if (b==0):
    return a
  return gcd(b,a%b)

Answer 2

You should return function call:

def gcd(a,b):
  if (b==0):
    return a
  return gcd(b,a%b)

Answer 3

Your code doesn't return the return value of the recursive call.

def gcd(a,b):
  if (b==0):
    return a
  return gcd(b,a%b)

This should work.