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Why C has Pointers.

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  Why C has Pointers. curixinfotech <curixinfotech.54dl3z@no-mx.forums.yourdomain.com.au> - 2011-12-07 07:22 -0500
    Re: Why C has Pointers. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-12-07 04:35 -0800
    Re: Why C has Pointers. Eric Sosman <esosman@ieee-dot-org.invalid> - 2011-12-07 07:58 -0500
      Re: Why C has Pointers. Mike Manilone <zhtx10@gmail.com> - 2011-12-07 13:15 +0000
        Re: Why C has Pointers. Bill Reid <hormelfree@gmail.com> - 2011-12-08 06:29 -0800
    Re: Why C has Pointers. Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-07 14:50 +0100
      Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-07 11:01 -0800
        Re: Why C has Pointers. Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-12-07 20:49 +0100
        Re: Why C has Pointers. Brian <nospam@nospam.com> - 2011-12-07 20:00 +0000
          Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-07 15:30 -0500
            Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-07 12:43 -0800
              Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-07 13:09 -0800
            Re: Why C has Pointers. Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-08 19:39 +0100
              Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-08 14:16 -0500
                Re: Why C has Pointers. Vincenzo Mercuri <vincenzo.mercuri@hotmail.it> - 2011-12-08 20:23 +0100
      Re: Why C has Pointers. Kaz Kylheku <kaz@kylheku.com> - 2011-12-07 20:48 +0000
        Re: Why C has Pointers. Vincenzo Mercuri <vincenzo.mercuri@yahoo.it> - 2011-12-07 22:07 +0100
        Re: Why C has Pointers. Jorgen Grahn <grahn+nntp@snipabacken.se> - 2011-12-10 07:34 +0000
    Re: Why C has Pointers. August Karlstrom <fusionfile@gmail.com> - 2011-12-07 16:16 +0100
    Re: Why C has Pointers. Borax Man <rotflol2@hotmail.com> - 2011-12-08 18:32 +1100
      Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-08 00:20 -0800
        Re: Why C has Pointers. André Gillibert <MetaEntropy.removeThis@gmail.com> - 2011-12-08 13:44 +0100
          Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-09 05:04 -0800
            Re: Why C has Pointers. gazelle@shell.xmission.com (Kenny McCormack) - 2011-12-09 14:59 +0000
              Re: Why C has Pointers. Malcolm McLean <malcolm.mclean5@btinternet.com> - 2011-12-09 20:19 -0800
              Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-10 07:36 -0800
    Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-08 00:12 -0800
    Re: Why C has Pointers. Cong Wang <xiyou.wangcong@gmail.com> - 2011-12-15 07:26 +0000
    Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-17 08:51 -0800
      Re: Why C has Pointers. Barry Schwarz <schwarzb@dqel.com> - 2011-12-17 10:10 -0800
        Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-17 14:28 -0600
          Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-17 15:00 -0600
          Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-17 13:55 -0800
            Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-17 18:27 -0600
              Re: Why C has Pointers. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-18 01:26 +0000
                Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-17 22:34 -0600
                  Re: Why C has Pointers. "Philip Lantz" <prl@canterey.us> - 2011-12-17 23:48 -0800
                    Re: Why C has Pointers. superpollo <superpollo@tznvy.pbz> - 2011-12-18 11:06 +0100
                  Re: Why C has Pointers. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-18 13:44 +0000
                  Re: Why C has Pointers. pete <pfiland@mindspring.com> - 2011-12-18 11:05 -0500
                  Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-18 11:50 -0500
                  Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-18 13:10 -0800
                    Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-27 16:03 -0600
                      Re: Why C has Pointers. Barry Schwarz <schwarzb@dqel.com> - 2011-12-27 14:40 -0800
                      Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-27 15:08 -0800
                        Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-27 20:09 -0600
                          Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-27 23:00 -0800
                          Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-28 02:53 -0800
                          Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-28 08:39 -0500
                      Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-27 18:14 -0500
                        Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-27 15:36 -0800
                          Re: Why C has Pointers. James Kuyper <jameskuyper@verizon.net> - 2011-12-27 18:53 -0500
                      Re: Why C has Pointers. Ben Bacarisse <ben.usenet@bsb.me.uk> - 2011-12-28 13:20 +0000
                  Re: Why C has Pointers. John Bode <jfbode1029@gmail.com> - 2011-12-28 08:42 -0800
                Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-17 20:36 -0800
                  Re: Why C has Pointers. Seebs <usenet-nospam@seebs.net> - 2011-12-18 04:56 +0000
                    Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-17 21:37 -0800
                      Re: Why C has Pointers. Seebs <usenet-nospam@seebs.net> - 2011-12-18 05:42 +0000
                        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-18 08:08 -0800
                          Re: Why C has Pointers. Robert Wessel <robertwessel2@yahoo.com> - 2011-12-18 10:36 -0600
                          Re: Why C has Pointers. Seebs <usenet-nospam@seebs.net> - 2011-12-18 18:50 +0000
                          Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-19 02:39 -0800
                          Re: Why C has Pointers. gordonb.1i27q@burditt.org (Gordon Burditt) - 2011-12-21 22:34 -0600
                        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-19 07:56 -0800
                          Re: Why C has Pointers. John Tsiombikas <nuclear@member.fsf.org> - 2011-12-19 18:38 +0000
                            Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-19 13:47 -0800
                              Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-28 02:58 -0800
                                Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-28 03:21 -0800
              Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-18 13:07 -0800
                Re: Why C has Pointers. "io_x" <a@b.c.invalid> - 2011-12-19 04:02 +0100
          Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-17 15:35 -0800
            Re: Why C has Pointers. ralph <nt_consulting64@yahoo.net> - 2011-12-17 18:41 -0600
          Re: Why C has Pointers. John Bode <jfbode1029@gmail.com> - 2011-12-19 05:14 -0800
        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-18 09:50 -0800
        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-09 15:48 -0800
          Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2012-01-10 00:21 -0800
            Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2012-01-10 01:03 -0800
      Re: Why C has Pointers. Keith Thompson <kst-u@mib.org> - 2011-12-17 11:45 -0800
        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-17 15:18 -0800
        Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-19 14:10 -0800
          Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-20 10:46 -0800
    Re: Why C has Pointers. "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-12-17 19:15 +0100
      Re: Why C has Pointers. "Skybuck Flying" <Windows7IsOK@DreamPC2006.com> - 2011-12-17 19:19 +0100
        Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-19 02:48 -0800
    Re: Why C has Pointers. 88888 Dihedral <dihedral88888@googlemail.com> - 2011-12-18 11:05 -0800
      Re: Why C has Pointers. Nick Keighley <nick_keighley_nospam@hotmail.com> - 2011-12-19 02:48 -0800

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#14799

On Tuesday, December 20, 2011 6:10:24 AM UTC+8, 88888 Dihedral wrote:
> On Sunday, December 18, 2011 3:45:14 AM UTC+8, Keith Thompson wrote:
> > 88888 Dihedral <dihe...@googlemail.com> writes:
> > > On Wednesday, December 7, 2011 8:22:56 PM UTC+8, curixinfotech wrote:
> > >> my Q is on the c language tell me now why c has pointers.
> > >> parshant
> > >
> > > OK, I'll explain how to use a pointer in C without any knowledge in the 
> > > hardware or assembly here.
> > > // 
> > > int i;
> > > int a[3]={ 1,2,3} ; // an array of 3 integers
> > > int* ptr1; // Note the star should be right after int, not initialize
> > 
> > Why should the * be adjacent to "int"?  My own preferred style (and, I
> > think, that of most C programmers) is:
> > 
> >     int *ptr1;
> > 
> > The syntax of declarations in C follows (more or less) the syntax of
> > expressions; "declaration follows use".  So "int *ptr;" says that *ptr
> > is an int -- from which it follows that ptr is a pointer to an int,
> > i.e., an int*.
> > 
> > This layout follows the grammar more closely, and makes an (admittedly
> > unwise) declaration like this:
> > 
> >     int *pointer, not_a_pointer;
> > 
> > easier to understand.
> > 
> > But there is a school of thought that prefers to put the * next to the
> > type name.  That seems to be the usual convention in C++.  That's ok if
> > you avoid declaring multiple variables in one declaration (which you
> > should probably do anyway).
> > 
> > Note that the same principle might suggest:
> > 
> >     int[3] arr;
> > 
> > which is of course a syntax error.
> > 
> > > int* ptr2; // not initialized
> > >
> > > ptr1=a; // Read this as  to make ptr1 to be an alias of a. 
> > 
> > That's not necessarily a good way to think of it.  Since "a" is an array
> > object the expression consisting of its name decays to a pointer to its
> > first element.  That pointer value is then stored in ptr1.  ptr1 points
> > to the first element of a.  To show that it's not a true alias, consider
> > sizeof a vs. sizeof ptr1.
> 
> I do not allocate arrays in the auto mode  very often in C. 
> But for an example, I just have to show the silly array allocated in the 
> auto mode. 
> 
> Normally I allocate a buffer from the heap by malloc. 
> Also I wrote functions that could  return  pointers  and have to clean up
> local buffers correctly before exiting the function.

 Also there's no need to free arrays on the stack of auto variables. 
One just has to clean those buffers from the heap exactly without errors. 

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#14658

From what I have read and vaguely remember:

C was once designed to be a "value language" this can still be seen today as 
C misses "call by reference" instead pointers need to be used.

Java attempted a similar idea but also failed and eventually 
pointers/references were added to Java.

So just like Java the C language designer ultimately came to the conclusion 
that C needs pointers too ! ;)

C# (sharp) attempted something like no pointers as well, ultimately it also 
needed some kind of pointer...

Bye,
  Skybuck :) 

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#14659

So to completely answer your question.

Pointer support is a basic language requirement for any serious language as 
data is stored in memory cells.

Without being able to address those memory cells, data could never be copied 
from cell to cell, a requirement which most computer programs have.

There might be a way around pointers by introducing instructions which read 
different memory cells, for example one above, one below or above and below 
the current instruction or data item.

How usefull such an instruction set would be remains to be seen, it's 
probably more an attempt at obfuscate logic then anything that can be taken 
seriously ;) and also rather limited ;)

Might as well use pointers instead.

Bye,
  Skybuck.

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#14745

On Dec 17, 6:19 pm, "Skybuck Flying" <Windows7I...@DreamPC2006.com>
wrote:

> So to completely answer your question.
>
> Pointer support is a basic language requirement for any serious language as
> data is stored in memory cells.

nonsense. many "serious" langauges manage without pointers.

> Without being able to address those memory cells, data could never be copied
> from cell to cell, a requirement which most computer programs have.

nonsense. Any lanaguage that supports assignment can copy data from
one "cell" to another. No pointers necessary.

You are confusing language with implementation in a manner that throws
away 50 years of programming experience. Why not just progarm in
assembler if you want access to the underlying hardware?

> There might be a way around pointers by introducing instructions which read
> different memory cells, for example one above, one below or above and below
> the current instruction or data item.

go and look at a few other programming languages.

> How usefull such an instruction set would be remains to be seen, it's
> probably more an attempt at obfuscate logic then anything that can be taken
> seriously ;) and also rather limited ;)
>
> Might as well use pointers instead.

I don't understand why they got rid of plug boards. Any serious
computer needs a plugboard to specify the data paths.

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#14697

It is simple in the math that the number of bits can represent is more powerful
when the number of bits grow with the implementation in the electronics industry.

Passing by an address of a fixed number of bits is  more efficient than a deep
copy proved. 

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#14743

On Dec 18, 7:05 pm, 88888 Dihedral <dihedral88...@googlemail.com>
wrote:
> It is simple in the math that the number of bits can represent is more powerful
> when the number of bits grow with the implementation in the electronics industry.
>
> Passing by an address of a fixed number of bits is  more efficient than a deep
> copy proved.

Haiku?

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