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From: ok@quintus.uucp (Richard A. O'Keefe)
Newsgroups: comp.lang.fortran
Subject: Re: Fortran versus C for numerical analysis
Message-ID: <406@quintus.UUCP>
Date: 15 Sep 88 07:12:29 GMT
References: <893@amelia.nas.nasa.gov> <3064@lanl.gov> <820@cernvax.UUCP>
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In article <820@cernvax.UUCP> hjm@cernvax.UUCP (Hubert Matthews) writes:
>      I = 5 / 4 * 5		(I gets 5 in F77, I gets something in C)
>
>Personally, I wouldn't use [this]; I would always enforce an evaluation order
>by using parentheses.  If this could be ambiguous in C, I wouldn't use it for
>numerical work.

This is not ambiguous in C, and never has been.
	% echo "I = 5 / 4 * 5;" | cparen
	I = ((5 / 4) * 5);

In fact, this is one of the reasons why some C programmers resent the
Fortran people telling them what to do with parentheses:  C programmers
are used to adding parentheses to expressions to clarify the grouping
*without* changing the semantics.  The point at issue is whether
	I = N * P * Q;
and	I = (N * P) * Q;
have the same meaning.  In pre-ANSI C, they did; a compiler could
rearrange both.  In the current draft, the two expressions are different,
exactly as in Fortran.