From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <775b8d190512152127j6e9fb048n8db2219b90877e8f@mail.gmail.com>
Date: Fri, 16 Dec 2005 16:27:42 +1100
From: Bruce Ellis <bruce.ellis@gmail.com>
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
Subject: Re: [9fans] More Microsoft bashing
In-Reply-To: <20051216050830.GE15067@augusta.math.psu.edu>
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References: <6e35c0620512152004n37c06ff5wd250424db50d874d@mail.gmail.com>
	<20051216045306.126521B12F3@dexter-peak.quanstro.net>
	<20051216050830.GE15067@augusta.math.psu.edu>
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any C standard since forever has stated clearly that the
behaviour is undefined.  i've never written a program that
mods a negative number.  have fun in portability.

brucee

On 12/16/05, Dan Cross <cross@math.psu.edu> wrote:
> On Thu, Dec 15, 2005 at 10:53:06PM -0600, erik quanstrom wrote:
> > | Please note that this definition of DIV and MOD differs from the
> > | definition given in [M. Reiser, N. Wirth. Programming in Oberon. p.
> > | 36]:
> > | x  =3D (x DIV y) * y + (x MOD y), and
> > | 0 <=3D (x MOD y) < y
>    ^^^^^^^^^^^^^^^^^^
> > |
> > | So, what *is* -5 MOD 3?
> > |
> >
> > -2
>
> Are you sure?  It looks to me more than it'd be +1.  Wirth's definition
> above would tend to indicate that x MOD y is always positive, unless I'm
> reading it wrong, or that's not the whole story (and I confess I'm too
> lazy to look up the definitions in context).  If I'm right, that would
> also imply that x DIV y tends more wards negative infinity than zero
> for negative numerators.
>
>        - Dan C.
>
>