Path: utzoo!attcan!uunet!lll-winken!lll-tis!ames!pasteur!ucbvax!husc6!xait!g-rh
From: g-rh@xait.CCA.COM (Richard Harter)
Newsgroups: comp.lang.c
Subject: Re: Array indexing vs. pointers...
Message-ID: <33488@xait.CCA.COM>
Date: 19 Sep 88 19:57:16 GMT
References: <8809191521.AA17824@ucbvax.Berkeley.EDU>
Reply-To: g-rh@XAIT.Xerox.COM (Richard Harter)
Organization: Xerox Corporation, Cambridge, Massachusetts
Lines: 39

In article <8809191521.AA17824@ucbvax.Berkeley.EDU> U23405@UICVM (Michael J. Steiner) writes:
>First, I have a question. How and why is array indexing slower than
>pointer arithmetic? They are very similar. Also, I think that compilers
>should automatically translate array indexing into pointer arithmetic when
>dealing with arrays in C. Any comments, opinions?

	Depends on the compiler, the machine, and the circumstances.  The
gain comes when you increment a pointer into the array rather than reference
the indexed array.  For example

	for (i=0;i