there is a problem, holp someone could help me,thanks

John Gordon gordon at panix.com
Wed Aug 24 18:46:39 CEST 2011


In <f99a156b-56b4-41f4-9599-0dcc31a47b0f at v9g2000pri.googlegroups.com> kangshufan at hotmail.com writes:

> Hi everyone

> I just study python for a few time.
> Now I have a problem and I holp someone can help me.
> There is a piece of code:

> def fib(x):
>     if x==0 or x==1: return 1
>     else: return fib(x-1) + fib(x-2)

> Could you explain how it works?
> Thanks for you help.

> Vince

When a function calls itself, as fib() does, it's called recursion.

  http://en.wikipedia.org/wiki/Recursion_(computer_science)

Basically the fib() method keeps calling itself with smaller and smaller
arguments until it gets 1 or 0.

-- 
John Gordon                   A is for Amy, who fell down the stairs
gordon at panix.com              B is for Basil, assaulted by bears
                                -- Edward Gorey, "The Gashlycrumb Tinies"




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