From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00 autolearn=ham
	autolearn_force=no version=3.4.4
X-Google-Language: ENGLISH,ASCII-7-bit
X-Google-Thread: 103376,287e8ed2b0c0aabf
X-Google-Attributes: gid103376,public
X-Google-ArrivalTime: 2002-07-31 12:14:10 PST
Newsgroups: comp.lang.ada
Path: 
 archiver1.google.com!news1.google.com!newsfeed.stanford.edu!news-spur1.maxwell.syr.edu!news.maxwell.syr.edu!newshosting.com!news-xfer1.newshosting.com!uunet!dca.uu.net!ash.uu.net!world!news
From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: Zeller's Algorithm
Sender: news@world.std.com (Mr Usenet Himself)
Message-ID: <wccvg6v1zj2.fsf@shell01.TheWorld.com>
Date: Wed, 31 Jul 2002 19:13:37 GMT
References: <3D3DED1F.24DE3AC8@lmco.com> <3D46CA0E.BCD17D9C@none.provided>
 <3D470EEE.811F758D@lmco.com> <719a5d07.0207310251.8f1adef@posting.google.com>
 <kzS19.1$dz5.0@nwrddc01.gnilink.net>
NNTP-Posting-Host: shell01.theworld.com
Organization: The World Public Access UNIX, Brookline, MA
X-Newsreader: Gnus v5.7/Emacs 20.7
Xref: archiver1.google.com comp.lang.ada:27528
Date: 2002-07-31T19:13:37+00:00
List-Id: <comp.lang.ada>

"Frank J. Lhota" <NOSPAM.lhota.adarose@verizon.net> writes:

> > This may be a problem in languages
> > such as C, where e.g. -30 % 7 = -2.
> 
> Actually, the C standard does not require that (-30) % 7 == (-2). The
> standard has somewhat loose requirements here that would allow the C "%"
> operator to behave either like the Ada "rem" operator, or like the Ada "mod"
> operator. The drive to standardize C, unfortunately, came after there were
> many divergent implementations of the language. The need to validate
> existing implementations tied the hands of the standards committee.

Doesn't this make the % operator totally useless for negative numbers?
I mean, how do you write code that gets some useful "right" answer,
if you're doing % on negative numbers?

- Bob