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From: pmontgom@sonia.math.ucla.edu (Peter Montgomery)
Newsgroups: comp.lang.c
Subject: Re: C history question
Keywords: C design, XOR
Message-ID: <1687@sunset.MATH.UCLA.EDU>
Date: 12 Sep 89 21:34:36 GMT
References: <575@calmasd.Prime.COM>
Sender: news@MATH.UCLA.EDU
Reply-To: pmontgom@math.ucla.edu (Peter Montgomery)
Organization: UCLA Mathematics Department
Lines: 22

In article <575@calmasd.Prime.COM> wlp@calmasd.Prime.COM (Walter Peterson) writes:
>C has bitwise operators for AND (&), OR (|) and XOR (^) and boolean 
>operator for AND (&&) and OR (||), but not for XOR (^^). Why?
>What happened to the boolean XOR operator ?  If && makes sense for the
>boolean AND and || makes sense for the boolean OR, why doesn't ^^ make
>sense for the boolean XOR ?

	I ask why C lacks &&= and ||=.  In FORTRAN, I often write code like

		allok = allok .and. a(i).gt.b(i)

C will let me write 

		allok = allok && a[i] > b[i];

but it seems in the language spirit to avoid repeating "allok"; 
shouldn't we be allowed to abbreviate this to

		allok &&= a[i] > b[i];
--------
        Peter Montgomery
        pmontgom@MATH.UCLA.EDU