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From: abv@pucc-h (David Stevens)
Newsgroups: net.lang.c
Subject: Re: Standard extensions (logical exclusive or)
Message-ID: <1461@pucc-h>
Date: Thu, 8-Nov-84 18:03:40 EST
Article-I.D.: pucc-h.1461
Posted: Thu Nov  8 18:03:40 1984
Date-Received: Sun, 11-Nov-84 20:26:44 EST
References: <> <352@digi-g.UUCP>, <1442@pucc-h> <374@petsd.UUCP>
Organization: Purdue University Computing Center
Lines: 32

<bugs bugs bugs>

Joe Orost says:

>I disagree.  The bitwise operators operate on every bit of their arguments,
>whereas the logical operators operate on zero -vs- non-zero.  Therefore, i^j
>is not the same as i^^j.  i^^j is equivalent to:
>	i?(j?0:1):(j?1:0)
>which is only the same as i^j when i and j are 0 or 1.
>
>Therefore, I vote for the ^^ operator.
>
>					regards,
>					joe
>

	I disagree with you. The two important features of && over & are
that 1) it is logical (not bitwise), and 2) it is short-circuit.
	Boolean expressions evaluate to 0 or 1, so ^==^^ in this case, and
since both expressions must be evaluated, you gain nothing by adding ^^.
If you are checking for "nonzeroness", then neither "a!=b" (as someone else
suggested) nor "a^b" is equivalent to a^^b, but the question here is whether,
for "nonzeroness", "(a!=0) != (b!=0)", or "(a!=0) ^ (b!=0)" is so ugly that
an extension to include ^^ is reasonable. If a and b are not *really* logical
expressions, then I say that what you want is "!=0", and not some magic to
make them be treated like logcial expressions. I vote no for ^^.
----------
						David L Stevens
		{decvax|harpo|ihnp4|inuxc|seismo|ucbvax}!pur-ee!pucc-h:abv

DISCLAIMER:
The opinions expressed above are not necessarily my own, or anyone else's.