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Groups > comp.lang.c > #57000

Re: Fortran Guy Learning C - Structures...

From Keith Thompson <kst-u@mib.org>
Newsgroups comp.lang.c
Subject Re: Fortran Guy Learning C - Structures...
Date 2015-02-05 08:48 -0800
Organization None to speak of
Message-ID <lnwq3wl2x6.fsf@nuthaus.mib.org> (permalink)
References <32aade7c-a60c-4d76-9b25-ddb285438ce2@googlegroups.com> <08f17b24-a4bb-4e3b-ba52-035287ab63a5@googlegroups.com> <ba44af53-b35b-4c7d-8f84-d25bf2ab9c59@googlegroups.com> <8d68369b-24e9-485a-aa58-07ed34a6aee9@googlegroups.com> <mauq74$684$1@dont-email.me>

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Richard Heathfield <rjh@cpax.org.uk> writes:
> On 05/02/15 03:41, jeffkrob16@gmail.com wrote:
> <snip>
>  > With pointers being abstract as they are (passing addresses & not 
> values),
>
> Er, what? NO! Who told you that?
>
> Pointers are VALUES, and C is pass-by-value. You always pass values in 
> C. An address value is still a value. This is REALLY important. If you 
> don't get this right, your mental model of the interaction between 
> pointers and functions will be a complete mess.
>
> Pointers are values. Addresses are values. C functions take values. Always.

To elaborate on that a bit:

Suppose you have

    void func1(int param);
    void func2(int *param);
    int var = 42;

Calling `func1(var)` passes the *value* of `var`, which happens to be 42.

Calling `func2(&var)` does not pass the value of `var`, but it does pass
a value.  The value it passes is the result of evaluating the expression
`&var`; it's a value that's of type `int*`.

Some languages other than C permit passing arguments by reference.
Passing the address of an object is how you *implement*
pass-by-reference in C.

C does not have pass-by-reference as a language feature.  You can
implement pass-by-reference in C by passing pointers (and the pointers
are of course passed by value).

Quite similarly, C does not have linked lists as a language feature.
You can implement linked lists in C using pointers.

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"

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Thread

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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