Path: utzoo!utgpu!water!watmath!clyde!att-cb!att-ih!pacbell!rtech!wong
From: wong@rtech.UUCP (J. Wong)
Newsgroups: comp.lang.c
Subject: Helpful C Hint
Keywords: ?: usage optimization
Message-ID: <1971@rtech.UUCP>
Date: 17 Apr 88 07:39:52 GMT
Organization: Relational Technology Inc. Alameda, CA 94501
Lines: 18

Here's an interesting optimization (of which I'm sure some are
already well aware :-)

Occassionally, I write a conditional as follows:

	if ( ( a && b ) || ( !a && c && d ) )
		error();

where "a" is often something like "version == 1".

I dislike doing this because the condition "a" gets evaluated twice.  
I just realized I could rewrite this using the "?:" operator to only
evaluate "a" once:

	if ( a ? ( b ) : ( c && d ) )
		error();

(Depending on your compiler, this may not be more optimal.)