Path: utzoo!attcan!uunet!lll-winken!lll-lcc!ames!umd5!uflorida!novavax!proxftl!bill
From: bill@proxftl.UUCP (T. William Wells)
Newsgroups: comp.misc
Subject: Re: Programming style with arrays, summary
Summary: go ahead, USE those templates ... here's how.
Keywords: programming style, arrays
Message-ID: <337@proxftl.UUCP>
Date: 18 Jun 88 22:01:15 GMT
References: <778@dick.cs.vu.nl>
Organization: Proximity Technology, Ft. Lauderdale
Lines: 26

In article <778@dick.cs.vu.nl>, dick@cs.vu.nl (Dick Grune) writes:
)       Two people argue convincingly that using the number of elements and
) using the address of the last+1 item is actually the same thing.  They advocate
) tests like:
)
)       if (p >= &array[N])
)               error(...);
)
) and loops like:
)
)       for (p = &array[0]; p < &array[N]; p++)
)               process(*p);
)
) both of which look sane and understandable.  I seriously thought about adopting
) these "templates" systematically in my coding, when I realized that for it to
) work, you would have to declare N as a long.  Otherwise you lose on machines
) with 2-byte ints and 4-byte pointers.

The new C standard has a fix for this.  One can even use this
with current code.  Declare any variable which contains the size
of an object as of type size_t.  If you are using Standard C,
include <stddef.h>; if not, add to your program an appropriate
typedef for it.  K&R compatible compilers would use typedef
unsigned size_t; compilers with longer addresses would use
typedef unsigned long size_t.  (There is an equivalent type for
the difference between two pointers, ptrdiff_t; I suggest using
this as well.