From mboxrd@z Thu Jan  1 00:00:00 1970
To: Fans of the OS Plan 9 from Bell Labs <9fans@cse.psu.edu>
From: "Brian L. Stuart" <blstuart@bellsouth.net>
Subject: Re: [9fans] More Microsoft bashing 
In-reply-to: Your message of Fri, 16 Dec 2005 00:08:30 -0500 .
	<20051216050830.GE15067@augusta.math.psu.edu> 
Date: Thu, 15 Dec 2005 23:19:35 -0600
Message-Id: <20051216052053.VFSC12897.ibm69aec.bellsouth.net@p1.stuart.org>
Topicbox-Message-UUID: c8f996be-ead0-11e9-9d60-3106f5b1d025

In message <20051216050830.GE15067@augusta.math.psu.edu>, Dan Cross writes:
>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  = (x DIV y) * y + (x MOD y), and
>> | 0 <= (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

This also matches Knuth's in Vol 1.  He states it as:

x mod y = x - y * floor( x / y )

and then observes that the mod follows the sign of y and that
the magnitude of the mod is strictly less than that of y.

Brian L. Stuart