Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c++ > #5967
| From | Thomas David Rivers <rivers@dignus.com> |
|---|---|
| Newsgroups | comp.lang.c++ |
| Subject | Re: Problem with array objects |
| Date | 2011-06-01 09:57 -0400 |
| Organization | Aioe.org NNTP Server |
| Message-ID | <4DE6453C.7080307@dignus.com> (permalink) |
| References | (23 earlier) <nVwEp.24865$h_.19621@newsfe30.ams2> <4DE2D8FA.6@dignus.com> <7fPEp.12138$El6.500@newsfe21.ams2> <4DE4F114.9040801@dignus.com> <VnbFp.20543$f95.5956@newsfe02.ams2> |
Paul wrote:
>
> "Thomas David Rivers" <rivers@dignus.com> wrote in message
> news:4DE4F114.9040801@dignus.com...
>
>> Paul wrote:
>>
>>>
>>> Yes I agree.
>>
>>
>>
>> That's great!
>>
>> So - now, given our understanding that an lvalue reference
>> to an array name is converted to be a pointer to the first element
>> of the array, we can examine things like array indexing (which
>> is really cool) and multiple dimension arrays...
>>
>> I propose we take a look at array indexing... would that be interesting?
>>
> I agree given that an array name is converted to a pointer to the
> array and not ONLY to a first element of the array.
> Can you agree that an array name converted to a pointer points to an
> array?
Oh - I'm sorry, but I can't, and when we get into how indexing works and
how arrays with multiple dimensions work I hope to motivate the argument
of why that isn't a correct characterization... but, that comes later.
That is, we need to be quite careful with the types of things; or the entire
mess comes crumbling down.
You see - there is the idea of a pointer to an array, and that is quite
different
from the idea of a pointer to an element of an array. One can imagine
that would
have to be the case, or else you could not distinguish between the
entire array
and an element of the array... which becomes paramount in the definition of
the indexing operation.
The language definition is quite precise that a pointer to an element of
an array
is nothing more than that; a pointer to one element of the array.
Since this could
easily be confused with the (real, although not yet
discussed/introduced) idea of
a pointer to an array then we have to stick with the language definition.
Again, when we consider how indexing works - this will become a very
important
distinction.
But, to movitate this, and "jump ahead" a little, this declaration
int (*ap)[5];
is a pointer to an array of 5 `int' elements. Those are the terms
reserved
by the language definition. "ap" is actually is a separate object (a
separate "box")
that points to 5 other `int' objects, thus "ap" is a pointer to an array
of 5 `int' elements.
That is very different from:
int *ip;
int array[5];
ip = array;
In this situation, it is very clear that `ip' is a pointer to an `int',
and that
it happens to point to the first `int' alement of array (because of the
rules
we've already discussed), but that's as far as the language definition
carries us.
But, "ip" is a box that can contain the location of an `int' box. "ap"
is a box
that can contain the location of an array of 5 `int' boxes... so, "ap"
and "ip"
are quite different types, different "kinds" of boxes.
And, as I mentioned before - that becomes very important when indexing
is defined.
So, while there may be other terms we could use, "pointer to an array"
has already
been taken by the language definition and is very well defined.
I could see myself throwing around some of the other words that have been
mentioned here (saying that, for example, a pointer points "into" an array.)
But those are colloquialisms without any formal definition... so, they
can mean
just about whatever anyone would like them to mean at any time, which makes
talking about them kinda difficult.
Maybe we could coin some new terms??? I would be happy to discuss them,
but I think they are outside the bounds of the C/C++ language definition.
(That is not to say that in some other programming language, or other
situation,
they would not be appropriate - I just believe that is not the correct
characterization
for C/C++, and certainly not in the spirit of the language definitions.)
- Dave Rivers -
--
rivers@dignus.com Work: (919) 676-0847
Get your mainframe programming tools at http://www.dignus.com
Back to comp.lang.c++ | Previous | Next — Previous in thread | Next in thread | Find similar
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 11:39 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-25 12:04 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 12:56 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-25 13:15 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 16:36 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-25 16:47 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 17:15 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-25 17:39 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 21:09 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-25 22:24 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-26 01:28 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-25 09:57 -0400
Re: Problem with array objects "Alf P. Steinbach /Usenet" <alf.p.steinbach+usenet@gmail.com> - 2011-05-25 16:50 +0200
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-25 12:01 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 16:59 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-25 12:56 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-25 21:46 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-25 20:02 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-26 01:37 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-26 09:08 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-26 15:19 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-26 14:45 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-26 21:02 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-27 09:34 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-27 14:46 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-27 15:07 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-27 21:42 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-27 19:34 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-28 01:24 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-28 10:58 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-28 19:41 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-28 20:38 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-29 12:32 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-29 10:05 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-29 20:13 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-29 19:38 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-30 17:01 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-05-31 09:45 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 20:33 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-06-01 09:57 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 15:53 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 16:46 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 19:44 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 19:59 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 21:41 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 22:10 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:39 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 23:21 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:32 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-06-01 12:33 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 19:18 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 19:38 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 20:10 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 20:18 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:01 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 22:25 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:43 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-06-02 09:49 +1200
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 23:27 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 00:26 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-02 00:33 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 08:52 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-06-01 15:37 -0400
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-06-02 07:46 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 21:22 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 10:31 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:10 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-06-02 09:28 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:59 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 15:05 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:35 +0100
Re: Problem with array objects Ian Collins <ian-news@hotmail.com> - 2011-06-02 10:51 +1200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 00:28 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 16:33 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 09:03 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-02 01:23 -0700
Re: Problem with array objects Miles Bader <miles@gnu.org> - 2011-06-02 17:31 +0900
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-02 01:39 -0700
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 11:28 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:54 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 12:08 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:41 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 14:56 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:17 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:17 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 15:32 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:58 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 16:31 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 08:50 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 21:05 +0100
Re: Problem with array objects Thomas David Rivers <rivers@dignus.com> - 2011-06-01 16:38 -0400
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:20 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 14:42 -0700
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-05-27 17:44 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-28 03:11 +0100
Re: Problem with array objects Öö Tiib <ootiib@hot.ee> - 2011-05-28 19:21 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-29 12:50 +0100
Re: Problem with array objects Öö Tiib <ootiib@hot.ee> - 2011-05-29 07:21 -0700
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-29 15:30 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-29 20:43 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-29 21:51 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 03:08 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-05-30 17:39 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 06:05 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-05-31 09:38 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 20:50 +0100
Re: Problem with array objects SG <s.gesemann@gmail.com> - 2011-05-31 02:23 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 13:29 +0100
Re: Problem with array objects "Fred Zwarts \(KVI\)" <F.Zwarts@KVI.nl> - 2011-05-31 15:17 +0200
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 20:43 +0100
Re: Problem with array objects Michael Doubez <michael.doubez@free.fr> - 2011-05-31 02:43 -0700
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-31 14:38 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-31 20:45 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-05-31 21:11 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 10:23 +0100
Re: Problem with array objects gwowen <gwowen@gmail.com> - 2011-06-01 03:08 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 15:59 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 13:45 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 14:23 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 16:02 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 16:33 +0100
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 19:52 +0100
Re: Problem with array objects Leigh Johnston <leigh@i42.co.uk> - 2011-06-01 20:02 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 09:16 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 21:00 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 10:09 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 22:31 +0100
Re: Problem with array objects Pete Becker <pete@versatilecoding.com> - 2011-06-01 11:58 -1000
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:21 +0100
Re: Problem with array objects crisgoogle <crisd@telus.net> - 2011-06-01 16:22 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 00:48 +0100
Re: Problem with array objects crisgoogle <crisd@telus.net> - 2011-06-02 11:06 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-02 19:58 +0100
Re: Problem with array objects crisgoogle <crisd@telus.net> - 2011-06-02 13:28 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-03 01:16 +0100
Re: Problem with array objects crisgoogle <crisd@telus.net> - 2011-06-02 18:51 -0700
Re: Problem with array objects PaulR <pchristor@yahoo.co.uk> - 2011-06-03 04:59 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-06-01 23:21 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-06-01 14:46 -0700
Re: Problem with array objects Michael Doubez <michael.doubez@free.fr> - 2011-06-01 00:46 -0700
Re: Problem with array objects "Paul" <pchristor@yahoo.co.uk> - 2011-05-29 20:29 +0100
Re: Problem with array objects Joshua Maurice <joshuamaurice@gmail.com> - 2011-05-29 23:11 -0700
csiph-web