Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!cica!gatech!galbp!advdev.LBP.HARRIS.COM!jsb
From: jsb@advdev.LBP.HARRIS.COM (FLEA)
Newsgroups: comp.lang.c
Subject: Re: swap(x,y)
Message-ID: <8514@galbp.LBP.HARRIS.COM>
Date: 22 Aug 89 19:12:30 GMT
References: <MYwDEFy00WB842JEUx@andrew.cmu.edu> <8350@boring.cwi.nl>
Reply-To: jsb@advdev.UUCP (FLEA)
Organization: /etc/organization
Lines: 21

In article <8350@boring.cwi.nl> tromp@piring.cwi.nl (John Tromp) writes:
:		 (Timothy R. Gottschalk) writes:
:
:>       To swap two variables x,y in C without using a temporary variable:
:
:>       /* begin swap */
:>       x += y;
:>       y = x - y;
:>       x -= y;
:>       /* end swap */
:
:>       Just curious...(this looks pretty valid) does anyone know an even
:
:How about
:
:x^=y^=x^=y;
:
:Avoids possible overflow problems and looks great in an
:Obfuscated C Code entry too!

Sorry, folks, both of these are illegal if x and y are pointers.