Path: utzoo!attcan!uunet!mcsun!hp4nl!philapd!ssp11!dolf
From: dolf@idca.tds.PHILIPS.nl (Dolf Grunbauer)
Newsgroups: comp.lang.c
Subject: Re: bug me now / bug me later
Message-ID: <789@ssp11.idca.tds.philips.nl>
Date: 14 Jun 90 13:44:35 GMT
References: <811@sagpd1.UUCP> <340021@hplvli.HP.COM>
Organization: Philips Information Systems, Apeldoorn, The Netherlands
Lines: 36

In article <340021@hplvli.HP.COM> boyne@hplvli.HP.COM (Art Boyne) writes:
<jharkins@sagpd1.UUCP (Jim Harkins) writes:
<
<>Lets say you have the following (you ADA people, please bear with me):
<>
<>	#define SIZE	6
<>	#define STEP	2
<>
<>Which is better:
<>
<>	a.	for(i = SIZE; i != 0; i -= STEP)
<>or
<>	b.	for(i = SIZE; i > 0; i -= STEP)
<>
<>Where this makes a difference is suppose SIZE is changed to 7.
<>'a' goes into an infinite loop, while 'b' stops.
<
<I would consider the following preferable:
<
<  if (SIZE % STEP != 0)
<	assert("SIZE not multiple of STEP in function ...");
<  for (i = SIZE; i > 0; i -= STEP)
How about:

#if (SIZE % STEP) != 0
	SIZE not multiple of STEP
#endif

As now the compiler complains at compile time or your code will
run faster. The compiler gives the line number as the line will
probably not be valid C. I am aware that this trick will not work when
SIZE & STEP (or at least one of them) are variables rather than macro's.
-- 
Dolf Grunbauer      Tel: +31 55 433233 Internet dolf@idca.tds.philips.nl
Philips Information Systems            UUCP     ...!mcsun!philapd!dolf
Some kind of happiness is measured out in miles