From: HaPK <theHaPK@...>
Date: 2005-09-15T23:45:05+09:00
Subject: Re: Math: sum and faculty

Daniel Schierbeck wrote:

> Range#sum
> =========

This could be done with Enumerable#inject. Your implementation assumes 
that range is for values of Float class.

> Integer#faculty
> ===============
>
> Implementation
> --------------
>
>   class Integer
>     def faculty
>       self == 0 ? 1 : self * (self - 1).faculty
>     end
>   end
>
(1..self).inject(1) { |result, x| result*x }

would be more compact.

Am I missing something, but why "faculty" ? Why not factorial ?