Why pointers?

[saneman]

I have written C++ code for some time now using both pointers and
references.

I was asked what the point was in using pointers and could not give a
short an explanatory example.

I would say that you use a pointer when data are updated across function
calls.

But does anyone have an idea to a minimal example where its impossible
to avoid pointer?

[pastbin@gmail.com]

Re: Why pointers?

[8.6] When should I use references, and when should I use pointers?

http://www.parashift.com/c++-faq-lite/references.html#faq-8.6

[Szabolcs Ferenczi]

Re: Why pointers?

On Feb 13, 10:57 pm, saneman <y...@dd.comwro te:

But does anyone have an idea to a minimal example where its impossible
to avoid pointer?

Think about polymorphism in C++.

Best Regards,
Szabolcs

[=?UTF-8?B?RXJpayBXaWtzdHLDtm0=?=]

Re: Why pointers?

On 2008-02-13 22:57, saneman wrote:

I have written C++ code for some time now using both pointers and
references.
>
I was asked what the point was in using pointers and could not give a
short an explanatory example.
>
I would say that you use a pointer when data are updated across function
calls.
>
But does anyone have an idea to a minimal example where its impossible
to avoid pointer?

In any situation where you need to be able to "reseat" the reference. On
example would be walking through the nodes in a linked list without
using recursion, something like:

node* n;
while (n != 0)
{
// do something with n
n = n->next;
}

--
Erik Wikström

[Salt_Peter]

Re: Why pointers?

On Feb 13, 5:24 pm, Szabolcs Ferenczi <szabolcs.feren ...@gmail.com>
wrote:

On Feb 13, 10:57 pm, saneman <y...@dd.comwro te:
>

But does anyone have an idea to a minimal example where its impossible
to avoid pointer?

>
Think about polymorphism in C++.
>
Best Regards,
Szabolcs

Polymorphism works quite nicely with references too.

[Juha Nieminen]

Re: Why pointers?

saneman wrote:

But does anyone have an idea to a minimal example where its impossible
to avoid pointer?

Try creating a linked list without pointers.

[Lionel B]

Re: Why pointers?

On Thu, 14 Feb 2008 14:00:10 +0200, Juha Nieminen wrote:

saneman wrote:

>But does anyone have an idea to a minimal example where its impossible
>to avoid pointer?

>
Try creating a linked list without pointers.

Sure it's possible... clunky, painful and probably inefficient, but
possible (e.g. use arrays for storage and arrays of indices for access).

--
Lionel B

[Pete Becker]

Re: Why pointers?

On 2008-02-14 10:35:15 -0500, Lionel B <me@privacy.net said:

On Thu, 14 Feb 2008 14:00:10 +0200, Juha Nieminen wrote:
>

>saneman wrote:

>>But does anyone have an idea to a minimal example where its impossible
>>to avoid pointer?

>>
>Try creating a linked list without pointers.

>
Sure it's possible... clunky, painful and probably inefficient, but
possible (e.g. use arrays for storage and arrays of indices for access).

But given that it's hypothetically impossible to give such an example
(a Turing machine doesn't have pointers), examples that are clunky,
painful, and inefficient without pointers are good answers.

--
Pete
Roundhouse Consulting, Ltd. (www.versatilecoding.com) Author of "The
Standard C++ Library Extensions: a Tutorial and Reference
(www.petebecker.com/tr1book)

[Daniel T.]

Re: Why pointers?

saneman <yyyy@dd.comwro te:

Sorry for the confusion. I would like an example where its impossible to
avoid use 'new' (dynamic allocation).
>
The reason is that I often use pointers and references but seldom the
keyword 'new'.

You seldom use the keyword 'new'? Sounds like you have answered your own
question. Try to go back and do the same thing without the keyword. :-)

In C++, you should be using 'new' very rarely.

[arnuld]

Re: Why pointers?

On Fri, 15 Feb 2008 07:19:02 -0500, Daniel T. wrote:

In C++, you should be using 'new' very rarely.

Oh.. I did not know that :(



--

http://lispmachine.wordpress.com/