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Path: utzoo!linus!decvax!cwruecmp!atvax!ncoast!bsa
From: bsa@ncoast.UUCP (Brandon Allbery)
Newsgroups: net.lang.c
Subject: Re: Standard extensions (logical exclusive or)
Message-ID: <480@ncoast.UUCP>
Date: Sat, 10-Nov-84 11:19:11 EST
Article-I.D.: ncoast.480
Posted: Sat Nov 10 11:19:11 1984
Date-Received: Tue, 13-Nov-84 06:51:37 EST
References: <374@petsd.UUCP> <3081@alice.UUCP>
Reply-To: bsa@ncoast.UUCP (Brandon Allbery)
Organization: North Coast XENIX, Cleveland
Lines: 35
Summary: 

> Article <3081@alice.UUCP>, from ark@alice.UUCP (Andrew Koenig)
+----------------
| Joseph Orost suggests a new operator ^^ such that
| 	a^^b
| would be equivalent to
| 	a? (b?0:1): (b?1:0)
| 
| What is wrong with writing
| 	a!=b
| for this purpose?

C programmers like to cut corners; witness all those on1 messages that
depend on && evaluating as little as possible.  It may be in K&R, but
I've seen too many harebrained implementations of too manu programs...

The problem with a!=b is that some of us use other corner-cutters:  one
of mine is

	if (index("AIJKLRaijklr", cmdchr)) dothis();

where index (strchr for USGers) returns either NULL or a pointer.  This
will NOT work if you use != for an xor:

	if (iscmd!=index("AIJKLRaijklr", cmdchr)) dothis();

is only true if !iscmd and !index(...), since index will usually NOT
return a 1...

--bsa
-- 
  Brandon Allbery @ North Coast Xenix  |   the.world!ucbvax!decvax!cwruecmp!
6504 Chestnut Road, Independence, Ohio |       {atvax!}ncoast!{tdi1!}bsa
   (216) 524-1416             \ 44131  | E1439@CSUOHIO.BITNET (friend's acct.)
---------------------------------------+---------------------------------------
			`Confusion is my natural state.'