[Tutor] recursion surprise

[Mark Lawrence]

On 08/06/2013 22:46, Jim Mooney wrote:
> I was trying out simple recursion as below, with the printout I
> expected, but it then also prints out "None" nine times. How does that
> work?
>
> Jim
>
> #Using Python 3.3.2 on Win 7 - standard project, standard test file
>
> def addone(num):
>      if num > 10:
>          return num
>      num = addone(num + 1)
        return None #Python puts the default return here as you don't 
specify it.
>
> print(addone(1))
>
> Result:
> 11
> None
> None
> None
> None
> None
> None
> None
> None
> None
>
>


-- 
"Steve is going for the pink ball - and for those of you who are 
watching in black and white, the pink is next to the green." Snooker 
commentator 'Whispering' Ted Lowe.

Mark Lawrence