2

I'm supposed to be writing a function that find the amount of shoes a given number of dogs would need. It can easily be done with multiplication, but we're required to use recursion, so i have

def dogShoes(n):
    total = 0
    if n>0:
        shoes =   n + dogShoes(n)
        total = total + 1
        if total == 4:
            return shoes

But I now realize that line 4 will go towards infinity and the bottom part that I though would stop it won't even be implemented. Is there a way to say when total is 4, stop and return the answer without shoes going towards infinity?

Eli Sadoff
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Malaikatu Kargbo
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3 Answers3

5

You can simplify your function a lot:

def dogShoes(n):
    if n == 0:
        return 0
    else:
        return 4 + dogShoes(n-1)

Since you have to use recursion instead of just returning n * 4 you can simply rewrite multiplication as addition (recursively).

What a weird task...

Keiwan
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2

You're calling your function recursively, but never changing the parameter, thus giving infinite recursion. Try:

>>> def dog_shoes(n):
...   if n > 0:
...     return 4 + dog_shoes(n-1)
...   else:
...     return 0
...
>>> dog_shoes(1)
4
>>> dog_shoes(2)
8
>>> dog_shoes(3)
12
Will
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0
def Mul(n, x):
    if n==1:
        return x
    else:
        return x+ Mul(n-1,x)

Here's a simple multiplication function using Python recursion using two arguments.

Mul(3,3)
>>>9
Yevhen Kuzmovych
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KingKong BigBong
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