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Re: i think i found

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In article <lnk42ocf5l.fsf@nuthaus.mib.org>,
Keith Thompson  <kst-u@mib.org> wrote:
>The array subscript operation is defined in terms of pointer
>arithmetic; E1[E2] is by definition identical to (*((E1)+(E2))).

What is 'array subscript'?

An array type is contiguous.  What does that mean?

    int f(int t)
    {
	int a[3];
	int *p;

	p = a;
	++p;
	*p = 1;
    }

As we expect, this stores in a consistent location.

An array of arrays is contiguous.  It doesn't say only the last
dimension is contiguous, all of them are.  So then the whole thing is.
And we have 'sizeof' to prove it.

    int g(int t)
    {
	int b[4][5];
	int *p;

	p = *a;
	p += 4;
	*p = 4;
	p += 2;
	*p = 6;
    }

If it breaks on the second one, then the array is not 'contiguous'.  

The compiler can't change it to 'int b[4][8];' because that's not
'contiguous' the way the programmer wanted.

I'm just using an 'int *' here.  It has to work the same as any other
'int *', pointing to the stack, from malloc, or whatever.  I don't think
it can 'remember' a bunch of extra stuff.

>It follows from that that your example's behavior is undefined.

unclear

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i think i found jgk@panix.com (Joe keane) - 2012-03-10 01:09 +0000
  Re: i think i found Ian Collins <ian-news@hotmail.com> - 2012-03-10 14:23 +1300
  Re: i think i found nick_keighley_nospam@hotmail.com - 2012-03-10 03:13 -0800
  Re: i think i found Barry Schwarz <schwarz45@yahoo.com> - 2012-03-10 09:17 -0800
    Re: i think i found pete <pfiland@mindspring.com> - 2012-03-10 19:22 -0500
      Re: i think i found James Kuyper <jameskuyper@verizon.net> - 2012-03-10 20:14 -0500
        Re: i think i found pete <pfiland@mindspring.com> - 2012-03-10 21:59 -0500
      Re: i think i found jgk@panix.com (Joe keane) - 2012-03-12 17:29 +0000
    Re: i think i found jgk@panix.com (Joe keane) - 2012-03-11 19:35 +0000
      Re: i think i found Keith Thompson <kst-u@mib.org> - 2012-03-11 13:06 -0700
        Re: i think i found jgk@panix.com (Joe keane) - 2012-03-13 20:27 +0000
          Re: i think i found Keith Thompson <kst-u@mib.org> - 2012-03-13 15:25 -0700
            Re: i think i found jgk@panix.com (Joe keane) - 2012-03-14 23:34 +0000
              Re: i think i found Eric Sosman <esosman@ieee-dot-org.invalid> - 2012-03-14 20:38 -0400
              Re: i think i found Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-15 18:03 -0700
                Re: i think i found jgk@panix.com (Joe keane) - 2012-03-17 17:34 +0000
                Re: i think i found Keith Thompson <kst-u@mib.org> - 2012-03-17 18:02 -0700
                Re: i think i found jgk@panix.com (Joe keane) - 2012-03-19 15:41 +0000
                Re: i think i found Tim Rentsch <txr@alumni.caltech.edu> - 2012-03-21 05:52 -0700

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