From: Dave Thomas <Dave@...>
Date: 2002-02-05T08:30:03+09:00
Subject: Re: Division Modulo Problem

"f. bou" <kanvas75@web.de> writes:

> Sorry a little failure.
> I got some nice division and module problems with Ruby 1.6.6:
> 9 / 2 = 4
> -9 / 2 = -5 ???
> 9 / -2 = -5 ???
> 9 % 2 = 1
> -9 % 2 = 1 ???
> 9 % -2 = -1 ???

Have you looked at the descriptions of class Numeric:

http://www.rubycentral.com/book/ref_c_numeric.html

(sorry about the table - it looks better in the printed book). The
relevant equation is

  q,r = x.divmod(y)

where

  q = floor(float(x)/float(y))
  r = x - q*y

Modulo always returns a number with the same sign as the divisor,
whereas remainder has the sign of the dividend.




Regards


Dave