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Re: Fortran Guy Learning C - Structures...

From glen herrmannsfeldt <gah@ugcs.caltech.edu>
Newsgroups comp.lang.c
Subject Re: Fortran Guy Learning C - Structures...
Date 2015-02-09 02:31 +0000
Organization Aioe.org NNTP Server
Message-ID <mb9658$l4$1@speranza.aioe.org> (permalink)
References (7 earlier) <ln7fvsjjzl.fsf@nuthaus.mib.org> <mb8fa5$9og$1@dont-email.me> <mb8fjl$atg$1@dont-email.me> <lnr3u0hz0k.fsf@nuthaus.mib.org> <rPQBw.36321$oR6.25972@fx01.iad>

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Lew Pitcher <lew.pitcher@digitalfreehold.ca> wrote:

(snip)

> Quote: "In C, by definition a two-dimensional array is really a
> one-dimensional array, each of whose elements is an array."

I suppose, but not quite as much as in COBOL. As I understand it
(never having actually written, or even compiled a program that
I didn't write in COBOL) that it only allows for 1D arrays.

If you want more than a 1D array, you have to use structures.
That is, you can have an array of structures, where each structure
member is also an array, but you can't have arrays of arrays.

There is a PL/I feature, which I believe came from COBOL, that
allows one to move the subscripts around between nesting levels.

Instead of saying A(I).B(J).C(K), one is allowed to say A.B.C(I,J,K).

So, it looks like a 3D array, but is actually an array of structures
of array of structure of array of structure.

In addition PL/I, and I believe also COBOL, allows one to omit
nesting levels where the result isn't ambiguous, such that you can
write C(I,J,K) without the A.B. qualifier, or maybe A.C(I,J,K) if
it would be ambiguous without the A, but not with A.

(PL/I does allow for more than 1D, but still has these features.)

But C arrays that are declared like:

int x[10][10];

act more like 2D arrays than arrays of arrays. Specifically, for
arrays or arrays one should be able to make the subarrays of
different lengths.

On the other hand, a Java array:

int [][] x=new int[10][10];

is really an array of 10 object references to 10 arrays. One can
change elements of x[i] to reference other arrays:

x[3]=new int[20];

and test the length of subarrays individually with

x[i].length.

The C array int x[10][10]; has 100 contiguous (at least as contiguous
as int y[100]) elements, and can be cast to a 1D array and dereferenced
as a 1D array.

-- glen

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Fortran Guy Learning C - Structures... jeffkrob16@gmail.com - 2015-02-03 09:33 -0800
  Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-03 17:59 +0000
  Re: Fortran Guy Learning C - Structures... James Kuyper <jameskuyper@verizon.net> - 2015-02-03 13:01 -0500
  Re: Fortran Guy Learning C - Structures... Barry Schwarz <schwarzb@dqel.com> - 2015-02-03 10:49 -0800
  Re: Fortran Guy Learning C - Structures... Richard Heathfield <invalid@see.sig.invalid> - 2015-02-03 18:54 +0000
  Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-03 11:50 -0800
    Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-03 12:07 -0800
    Re: Fortran Guy Learning C - Structures... Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-02-03 15:14 -0500
    Re: Fortran Guy Learning C - Structures... Barry Schwarz <schwarzb@dqel.com> - 2015-02-03 15:06 -0800
      Re: Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-03 22:19 -0800
  Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-03 21:40 +0000
    Re: Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-03 22:56 -0800
      Re: Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-03 23:02 -0800
      Re: Fortran Guy Learning C - Structures... asetofsymbols@gmail.com - 2015-02-04 00:01 -0800
  Re: Fortran Guy Learning C - Structures... jeffkrob16@gmail.com - 2015-02-04 10:53 -0800
    Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-04 11:21 -0800
    Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-04 19:32 +0000
    Re: Fortran Guy Learning C - Structures... Barry Schwarz <schwarzb@dqel.com> - 2015-02-04 11:59 -0800
    Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-04 15:30 -0800
      Re: Fortran Guy Learning C - Structures... jeffkrob16@gmail.com - 2015-02-04 19:41 -0800
        Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-05 04:06 +0000
          Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-05 10:36 +0000
            Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-05 10:59 +0000
            Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-05 11:03 +0000
            Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-05 12:30 +0000
              Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-05 12:46 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-05 12:49 +0000
            Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-05 15:08 -0800
          Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-05 08:48 -0800
          Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-05 15:16 -0800
            Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-05 23:35 +0000
              Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-07 12:11 -0800
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-07 12:22 -0800
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-07 22:03 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-07 14:47 -0800
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-07 17:15 -0800
                Re: Fortran Guy Learning C - Structures... Ian Collins <ian-news@hotmail.com> - 2015-02-08 17:22 +1300
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-08 02:47 -0800
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 11:20 -0800
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-08 14:36 -0800
                Re: Fortran Guy Learning C - Structures... Ian Collins <ian-news@hotmail.com> - 2015-02-09 11:51 +1300
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 15:02 -0800
                Re: Fortran Guy Learning C - Structures... Geoff <geoff@invalid.invalid> - 2015-02-08 16:55 -0800
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-09 03:24 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 11:56 +0000
                Re: Fortran Guy Learning C - Structures... David Brown <david.brown@hesbynett.no> - 2015-02-09 14:25 +0100
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 14:00 +0000
                Re: Fortran Guy Learning C - Structures... David Brown <david.brown@hesbynett.no> - 2015-02-09 15:26 +0100
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 14:39 +0000
                Re: Fortran Guy Learning C - Structures... David Brown <david.brown@hesbynett.no> - 2015-02-09 16:59 +0100
                Re: Fortran Guy Learning C - Structures... raltbos@xs4all.nl (Richard Bos) - 2015-02-09 16:01 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-09 13:39 +0000
                Re: Fortran Guy Learning C - Structures... James Kuyper <jameskuyper@verizon.net> - 2015-02-09 09:46 -0500
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 14:50 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-09 08:22 -0800
                Re: Fortran Guy Learning C - Structures... gazelle@shell.xmission.com (Kenny McCormack) - 2015-02-09 13:24 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-09 16:03 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-09 11:01 -0800
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-09 21:54 +0000
                Re: Fortran Guy Learning C - Structures... Öö Tiib <ootiib@hot.ee> - 2015-02-09 19:22 -0800
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-10 11:34 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-10 14:15 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-10 00:38 -0800
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-10 09:21 +0000
                Re: Fortran Guy Learning C - Structures... Ian Collins <ian-news@hotmail.com> - 2015-02-10 22:24 +1300
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-10 09:25 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-10 09:03 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-10 17:12 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-10 09:56 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-10 18:12 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-10 11:24 -0800
                Re: Fortran Guy Learning C - Structures... gazelle@shell.xmission.com (Kenny McCormack) - 2015-02-10 20:18 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-10 09:16 -0800
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-10 22:12 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-11 02:58 +0000
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-10 19:00 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-11 07:56 +0000
                Re: Fortran Guy Learning C - Structures... David Thompson <dave.thompson2@verizon.net> - 2015-02-22 18:08 -0500
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-10 16:01 -0800
                Re: Fortran Guy Learning C - Structures... Ian Collins <ian-news@hotmail.com> - 2015-02-10 11:26 +1300
                Re: Fortran Guy Learning C - Structures... David Brown <david.brown@hesbynett.no> - 2015-02-10 10:29 +0100
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-09 08:32 -0800
                Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-09 11:09 -0800
                Re: Fortran Guy Learning C - Structures... gazelle@shell.xmission.com (Kenny McCormack) - 2015-02-09 19:39 +0000
                Re: Fortran Guy Learning C - Structures... Martin Shobe <martin.shobe@yahoo.com> - 2015-02-09 14:04 -0600
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-09 12:24 -0800
                Re: Fortran Guy Learning C - Structures... David Brown <david.brown@hesbynett.no> - 2015-02-10 10:34 +0100
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 11:42 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-07 22:50 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-07 17:07 -0800
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 11:29 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-08 12:14 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 13:44 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-08 22:39 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 11:12 -0800
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 20:01 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 20:06 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 21:04 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 21:11 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-08 23:48 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 13:30 -0800
                Re: Fortran Guy Learning C - Structures... Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2015-02-08 16:47 -0500
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 14:53 -0800
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-09 02:31 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-09 10:35 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-09 13:57 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-09 07:59 -0800
                Re: Fortran Guy Learning C - Structures... Öö Tiib <ootiib@hot.ee> - 2015-02-09 18:15 -0800
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-10 05:54 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-09 16:17 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 22:04 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 14:57 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 23:45 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-09 02:53 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 09:29 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-09 10:10 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 11:24 +0000
                Re: Fortran Guy Learning C - Structures... Ike Naar <ike@iceland.freeshell.org> - 2015-02-09 17:36 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-09 17:56 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-09 10:51 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-09 11:10 +0000
                Re: Fortran Guy Learning C - Structures... Ben Bacarisse <ben.usenet@bsb.me.uk> - 2015-02-09 11:25 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-09 11:43 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-10 02:13 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-10 03:26 +0000
                Re: Fortran Guy Learning C - Structures... raltbos@xs4all.nl (Richard Bos) - 2015-02-09 21:18 +0000
                Re: Fortran Guy Learning C - Structures... Bartc <bc@freeuk.com> - 2015-02-09 23:11 +0000
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 12:10 +0000
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-08 11:18 -0800
                Re: Fortran Guy Learning C - Structures... Richard Heathfield <rjh@cpax.org.uk> - 2015-02-08 19:27 +0000
                Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-09 15:00 -0800
                Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-09 16:00 -0800
        Re: Fortran Guy Learning C - Structures... Malcolm McLean <malcolm.mclean5@btinternet.com> - 2015-02-05 02:49 -0800
          Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-05 11:16 +0000
          Re: Fortran Guy Learning C - Structures... Keith Thompson <kst-u@mib.org> - 2015-02-05 09:00 -0800
            Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-06 00:29 +0000
              Re: Fortran Guy Learning C - Structures... Robert Wessel <robertwessel2@yahoo.com> - 2015-02-05 19:20 -0600
              Re: Fortran Guy Learning C - Structures... "Charles Richmond" <numerist@aquaporin4.com> - 2015-02-06 16:15 -0600
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-07 00:57 +0000
              Re: Fortran Guy Learning C - Structures... Kaz Kylheku <kaz@kylheku.com> - 2015-02-07 01:40 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-07 08:22 +0000
                Re: Fortran Guy Learning C - Structures... glen herrmannsfeldt <gah@ugcs.caltech.edu> - 2015-02-07 12:06 +0000
            Re: Fortran Guy Learning C - Structures... John Bode <jfbode1029@gmail.com> - 2015-02-06 15:03 -0800
        Re: Fortran Guy Learning C - Structures... hormelfree@gmail.com - 2015-02-05 15:12 -0800

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