Xref: utzoo comp.lang.c:12569 comp.lang.fortran:1094
Path: utzoo!attcan!uunet!husc6!bloom-beacon!tut.cis.ohio-state.edu!mailrus!ames!haven!ncifcrf!nlm-mcs!adm!smoke!gwyn
From: gwyn@smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c,comp.lang.fortran
Subject: Re: C associativity rules
Keywords: associativity, expressions
Message-ID: <8483@smoke.ARPA>
Date: 13 Sep 88 13:45:48 GMT
References: <412@marob.MASA.COM>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 18

In article <412@marob.MASA.COM> samperi@marob.MASA.COM (Dominick Samperi) writes:
>Does K&R C or the new ANSI C permit the compiler to evaluate an expression
>like a+b+c in any order it pleases, rather than in the strict left-to-right
>order (a+b)+c ? I've always assumed that a strict left-to-right order would
>be used, as is the case for relational expressions like the one in the
>following.
>		while(i != -1 && a[i] != k)

Why burden the net with this when it is easy to find in K&R?
The theoretically associative and commutative operators have
always been allowed to be rearranged in C.  Before ANSI C (which
hasn't happened yet!), this was true even if the programmer
tried to enforce a particular grouping with parentheses (unlike
Fortran).

The operands of || and && operators obviously cannot be evaluated
in reverse order due to the very definition of the || and &&
operators.