Python 3 Why returns None

Question

Why is None returned ? When a or b is 0, max(a, b) must be returned

def gcd(a, b):
if a == 0 or b == 0:
    return max(a, b)
else:
    if a > b:
        gcd(a-b, b)
    else:
        gcd(b-a, a)

print(gcd(1000,400))

Your indentation is broken, make sure this is not the case in the code you actually run. — ctenar, Mar 10 '20 at 08:19

score 3 · Accepted Answer · answered Mar 10 '20 at 08:19

3

You aren't returning when you recursively call gcd.

def gcd(a, b):
    if a == 0 or b == 0:
        return max(a, b)
    else:
        if a > b:
            return gcd(a - b, b)
        else:
            return gcd(b - a, a)

answered Mar 10 '20 at 08:19

AKX

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Python 3 Why returns None

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