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From: walter@hpclwjm.HP.COM (Walter Murray)
Newsgroups: comp.std.c
Subject: Re: Re: Order of Evaluation (plus ?'s)
Message-ID: <12570034@hpclwjm.HP.COM>
Date: 20 Nov 89 18:42:58 GMT
References: <1989Nov18.232326.23711@utzoo.uucp>
Organization: Hewlett-Packard Calif. Language Lab
Lines: 21

Doug Gwyn writes:
> In article <13871@orstcs.CS.ORST.EDU> bailey@jacobs.CS.ORST.EDU.UUCP (Kirk Bailey) writes:
> -I'm curious about the fate of the changed floating point evaluation
> -constraints which were a part of some of the intermediate dpANSI "C" documents;
> -the idea being that the programmer could be assured of a fixed evaluation
> -order without requiring the use of temps.  The current doc's I have seem to
> -no longer mention this (or the synchronization aspect of unary '+')?

> Unary + is no longer the way to do this.  Use parentheses instead.

There are times when the parentheses aren't even needed.  ANSI C guarantees
that
   p = q + r + s;
will behave exactly the same as
   p = (q + r) + s;
In this respect a standard-conforming C compiler will actually have
less latitude than a FORTRAN compiler when it comes to rearranging
expressions.

Walter Murray
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