Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!hplabs!pyramid!infmx!kevinf
From: kevinf@infmx.UUCP (Kevin Franden)
Newsgroups: comp.lang.c
Subject: Re: Adding two pointers
Message-ID: <1321@infmx.UUCP>
Date: 10 May 89 19:50:27 GMT
References: <2765@buengc.BU.EDU> <563@lzaz.ATT.COM> <4093@ficc.uu.net> <922@garcon.cso.uiuc.edu> <924@garcon.cso.uiuc.edu> <113@ssp1.idca.tds.philips.nl>
Reply-To: kevinf@infmx.UUCP (Kevin Franden)
Organization: Informix, Menlo Park, Ca. U.S.A.
Lines: 37


Assuming that there does exist an application that wnats/needs to add
pointers, why won't this 'model' work?

	Assume an array a to be made up of elements of
	arbitrary size.  Assume further that this array has
	100 elements arranged (as we know C does) contiguously
	in memory.

	if p1 is pointing to element 37 and p2 is pointing to
	element 4, I'd like p3 to point to a[37+4] or a[41].
	
	struct{...}foo;

	foo p1,p2,p3;

	x=37;
	y=4;

	p1=a[x];
	p2=a[y];
	p3=(x+y)*sizeof(foo);


I realize that I missed part of this discussion, sorry if this has been
posted already, but won't p3 be pointing to the 41st element?  if this
is true, this is pointer addition, no?


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Kevin Franden		    UUCP: {backbone}!pyramid!infmx!kevinf
Informix Software Inc
disclaimer("I said what I said and not my employer");
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