Why is my Python function returning None?

January 12, 2022

I’m new to python and I tried creating a GCD function using Eucliean’s Algorithm. But any time I try to print the answer, it returns none. May someone let me know what I’m doing wrong.

Code:

def gcd(a,b):
    if a - b != 0:
        b = b - a
        b = abs(b)
        if a > b:
            a,b = b, a
            return gcd(a,b)
            
        else:
            gcd(a,b)
    else: 
        print(a)

x = input("Give First Num... ")

y = input("Give Second Num... ")

answer = gcd(int(x), int(y))

print("GCD = {}".format(answer))

Console:

120
GCD = None

>Solution :

To return something, there is just a minor adjustment to make on your code :

def gcd(a,b):
    if a - b != 0:
        b = b - a
        b = abs(b)
        if a > b:
            a,b = b, a
            return gcd(a,b)
            
        else:
            return gcd(a,b)
    else: 
        return a

Written this way, your function will always return something assigned to answer.