Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!ames!lll-winken!xanth!kremer
From: kremer@cs.odu.edu (Lloyd Kremer)
Newsgroups: comp.lang.c
Subject: Re: Another silly question
Summary: they're defined to be identical
Message-ID: <8662@xanth.cs.odu.edu>
Date: 27 Apr 89 16:04:20 GMT
References: pointer array reference access element <2459@nmtsun.nmt.edu>
Organization: Old Dominion University, Norfolk, Va.
Lines: 36


In article <2459@nmtsun.nmt.edu> kelly@nmtsun.nmt.edu (Sean Kelly) writes:

>My CS instructor and I disagree about a certain moot point.  I have a text
>book which says that
>
>	*(a + i)	and	a[i]
>
>are equivalent, given an array a, and int index i ... each gives the
>value stored in a[i].  But he says that
>
>	*(a + i)
>
>is non-standard and would not expect it do go far on all _real_ C compilers


The expressions *(a + i) and a[i] are absolutely synonymous in every way.
Either one could be defined as the other.  This fact is one of the foundational
pillars of the C Language.

Any C compiler that does not agree with this lacks knowledge of the most basic
fundamentals of the language and does not deserve to be called a C compiler.
I am tempted to make analogous remarks about C instructors.

An interesting corollary of this rule, often used in intentionally obfuscated
code, is:

	a[i]  ==  *(a + i)  ==  *(i + a)  ==  i[a]

Ask your instructor what he thinks 1["hello"] will evaluate to!

-- 
					Lloyd Kremer
					Brooks Financial Systems
					...!uunet!xanth!brooks!lloyd
					Have terminal...will hack!