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From: Maciej Sobczak <no.spam@no.spam.com>
Newsgroups: comp.lang.ada
Subject: Re: Negative float problem
Date: Thu, 03 Nov 2005 16:02:05 +0100
Organization: CERN - European Laboratory for Particle Physics
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Xref: g2news1.google.com comp.lang.ada:6145
Date: 2005-11-03T16:02:05+01:00
List-Id: <comp.lang.ada>

Jean-Pierre Rosen wrote:

> For example, try to find what "%" does in C/C++ (with at least one 
> negative operand, of course)...

For fundamental types, this always holds (except when b is 0):

a == (a / b) * b + a % b

If any of a or b is negative, then the sign of a % b is 
implementation-defined.

(for user-defined types - like MySuperSafeIntegerWithLotsOfChecks - it's 
of course whatever you invent it to be)

I have to admit that I was never concerned with this rule, I just don't 
divide modulo negative numbers - this kind of operation simply has no 
meaning in any of the domains where I used C/C++.


-- 
Maciej Sobczak : http://www.msobczak.com/
Programming    : http://www.msobczak.com/prog/