Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ncar!gatech!rutgers!att!lznv!jlw
From: jlw@lznv.ATT.COM (J.L.WOOD)
Newsgroups: comp.unix.questions
Subject: Re: Re^2: Bit Switching - How?
Summary: warning
Keywords: bits, flip
Message-ID: <1574@lznv.ATT.COM>
Date: 7 Apr 89 21:25:15 GMT
References: <1138@uvm-gen.UUCP> <9977@smoke.BRL.MIL> <2345@van-bc.UUCP> <2255@solo5.cs.vu.nl>
Organization: AT&T ISL Lincroft NJ USA
Lines: 14

> sl@van-bc.UUCP (pri=-10 Stuart Lynne) writes:
> \For fast generic swapping I use:
> 
> \#define	swap(a,b) {a^=b;b^=a;a^= b;}
> 

Also be careful how you use this algorithm if you are using pointers.
I once used this method in a sorting routine as my basic exchange and
got badly burned.

If a and b point to the same location, you get zero as in 0, nada, goose egg.

Joe Wood
jlw@lznv.ATT.COM