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From: g-rh@cca.CCA.COM (Richard Harter)
Newsgroups: comp.lang.c
Subject: Re: Writing readable code
Message-ID: <17171@cca.CCA.COM>
Date: Sat, 27-Jun-87 03:41:02 EDT
Article-I.D.: cca.17171
Posted: Sat Jun 27 03:41:02 1987
Date-Received: Sun, 28-Jun-87 01:01:58 EDT
References: <1158@copper.TEK.COM> <6858@auspyr.UUCP>
Reply-To: g-rh@CCA.CCA.COM.UUCP (Richard Harter)
Organization: Computer Corp. of America, Cambridge, MA
Lines: 53

In article <6858@auspyr.UUCP> mick@auspyr.UUCP (Mick Andrew) writes:
>
>I agree 99.9% with all of his comments on coding style, especially
>the awful habit of making code "better" by reducing the total character count.
>
>In the spirit of
> 		if(p != NULL)  vs.    if(!p)
>
>I offer one of my favourite obfuscated one liners:
>
>		if (strcmp(s1, s2) == 0)     vs.   if (!strcmp(s1, s2))
>
>
>In general, I try to use the yardstick, 
>"if it seems like a neat trick, don't do it!"

	Speaking as one who distinctly falls into the "not minimizing the
total character count" school, I fear I must disagree with these specific
examples.  When I see 

	if (!p)

I read it as

	if p is not valid then ...

The (!p) syntax tells me that p is among the class of items that may be
treated as boolean (under the C language conventions) and that we are
testing whether it is false.  This is not a matter of "saving characters";
it is a matter of classification.  When I see

	if (p != NULL)

it tells me two rather different things.  First of all it tells me that
p is an item for which there are one or more coded values, among which
is NULL, and that for all cases where p is not NULL, there is some action
to be taken.  Secondly it tells me that the file that the statement is in
includes stdio.h (or that the author of the code is a dweeb.)  And that
should tell me that the code in this file needs stdio.h, FOR I DO NOT
CONSIDER IT GOOD PROGRAMMING PRACTICE TO INCLUDE INCLUDE FILES WHICH ARE
NOT USED.

	This is not an issue of compactness; rather it is an issue of
clarity of format.  Different people, different strokes, and all that.
My vote is for simple clear code, generously commented.  But clarity is
relative -- if you understand the principles of a particular algorithm
or language or the standard conventions of a large program then a piece
of code may be quite clear to you and cryptic to someone without that
understanding.  And I do not really see that one can claim to understand
C and also claim that 'if (!p)' is obscure.
-- 

Richard Harter, SMDS Inc. [Disclaimers not permitted by company policy.]