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From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.lang.c
Subject: Re: swap(x,y)
Message-ID: <10799@smoke.BRL.MIL>
Date: 23 Aug 89 04:31:41 GMT
References: <MYwDEFy00WB842JEUx@andrew.cmu.edu>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 7

In article <MYwDEFy00WB842JEUx@andrew.cmu.edu> tg1e+@andrew.cmu.edu (Timothy R. Gottschalk) writes:
>       x += y;
>       y = x - y;
>       x -= y;

This is an old trick (usually done using XOR instead of + and -).  Your
version can fail if arithmetic overflow occurs.