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From: Dan Nagle <dnagle@erols.com>
Subject: Re: Zeller's Algorithm
Date: Wed, 31 Jul 2002 17:15:51 -0400
Date: 2002-07-31T21:17:02+00:00	[thread overview]
Message-ID: <5lkgkukkd7ofjmdpkpfd89n33vf93b8aen@4ax.com> (raw)
In-Reply-To: 1028145549.13341@master.nyc.kbcfp.com

Hello,

The Fortran 95 standard has two intrinsic functions,
mod() and modulo(), which have subtly different definitions.

I wonder which one the C++ committee thought they were modeling?

BTW, the Fortran 2000 standard doesn't change anything here,
so you can check this for free at http://www.j3-fortran.org
and clicking on Fortran 200x for a few megabytes of PDF
of the current draft standard.

-- 
Cheers!

Dan Nagle
Purple Sage Computing Solutions, Inc.

On Wed, 31 Jul 2002 16:01:27 -0400, Hyman Rosen <hyrosen@mail.com>
wrote:

>Darren New wrote:
>> Robert A Duff wrote:
>>>Doesn't this make the % operator totally useless for negative numbers?
>> Yes.
>
>No. It is required in C or C++ that for non-zero b,
>	a / b * b + a % b == a
>
>When division rounds towards zero, as is usually desired
>(the C++ standard claims that this is what the Fortran
>standard requires), this forces the remainder operation
>to return negative results. Eg., we want -3 / 2 == -1,
>so we must have -3 % 2 == -1 for the requirement to hold.




  parent reply	other threads:[~2002-07-31 21:15 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2002-07-23 23:56 Zeller's Algorithm Paul A Storm
2002-07-24  7:59 ` Thomas Wolf
2002-07-24 21:30   ` Paul A Storm
2002-07-29  8:29     ` Thomas Wolf
2002-07-30  4:35       ` Robert Dewar
2002-07-30  8:20         ` Thomas Wolf
2002-07-30 17:17 ` Rick Maffei
2002-07-30 22:10   ` Paul A Storm
2002-07-31 10:51     ` Thomas Wolf
2002-07-31 14:33       ` Frank J. Lhota
2002-07-31 19:13         ` Robert A Duff
2002-07-31 19:26           ` Darren New
2002-07-31 20:01             ` Hyman Rosen
2002-07-31 20:15               ` Frank J. Lhota
2002-07-31 21:08               ` Robert A Duff
2002-07-31 22:34                 ` Hyman Rosen
2002-07-31 22:57                   ` Robert A Duff
2002-08-01 15:17                     ` Hyman Rosen
2002-08-01 16:41                       ` Frank J. Lhota
2002-07-31 21:15               ` Dan Nagle [this message]
2002-07-31 22:36                 ` Hyman Rosen
2002-07-31 22:23         ` Matthew Woodcraft
2002-08-02  7:21         ` Thomas Wolf
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