Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c++ > #37142 > unrolled thread

:: scope resolution operator

Back to article view | Back to comp.lang.c++

Contents

  :: scope resolution operator Doug Mika <dougmmika@gmail.com> - 2015-07-17 09:52 -0700
    Re: :: scope resolution operator red floyd <no.spam@its.invalid> - 2015-07-17 10:08 -0700
    Re: :: scope resolution operator Doug Mika <dougmmika@gmail.com> - 2015-07-17 11:10 -0700
      Re: :: scope resolution operator Paavo Helde <myfirstname@osa.pri.ee> - 2015-07-17 14:16 -0500
      Re: :: scope resolution operator Öö Tiib <ootiib@hot.ee> - 2015-07-17 12:27 -0700
    Re: :: scope resolution operator Jorgen Grahn <grahn+nntp@snipabacken.se> - 2015-07-17 18:51 +0000
    Re: :: scope resolution operator Louis Krupp <lkrupp@nospam.pssw.com.invalid> - 2015-07-19 04:49 -0600
      Re: :: scope resolution operator legalize+jeeves@mail.xmission.com (Richard) - 2015-07-20 18:59 +0000
        Re: :: scope resolution operator red floyd <no.spam.here@its.invalid> - 2015-07-21 08:19 -0700

#37142 — :: scope resolution operator

Hi to all

I have been reading about C++ for a while, but I must admit, that one of the things that I find confusing is all the instances when you use the scope resolution operator ::.  Namespaces, inheritence, etc...

So it begs the question, when we write vector<int>::const_iterator myIterator
can I deduce from this that const_iterator is an inner class of vector<int> class?  Is it?

Does anyone know of a easy to read and comprehensive introduction to how/when/why to use the scope resolution operator?

[toc] | [next] | [standalone]

#37144

On 7/17/2015 9:52 AM, Doug Mika wrote:
> Hi to all
>
> I have been reading about C++ for a while, but I must admit, that one of the things that I find confusing is all the instances when you use the scope resolution operator ::.  Namespaces, inheritence, etc...
>
> So it begs the question, when we write vector<int>::const_iterator myIterator
> can I deduce from this that const_iterator is an inner class of vector<int> class?  Is it?
>

No. It is a *typename* that is defined within vector<int>.   It is not
necessarily an inner class.

Example:

class A {
public:
     typedef int integral_type;
};

A::integral_type x = 0;

x is of type int.

[toc] | [prev] | [next] | [standalone]

#37148

On Friday, July 17, 2015 at 11:52:39 AM UTC-5, Doug Mika wrote:
> Hi to all
> 
> I have been reading about C++ for a while, but I must admit, that one of the things that I find confusing is all the instances when you use the scope resolution operator ::.  Namespaces, inheritence, etc...
> 
> So it begs the question, when we write vector<int>::const_iterator myIterator
> can I deduce from this that const_iterator is an inner class of vector<int> class?  Is it?
> 
> Does anyone know of a easy to read and comprehensive introduction to how/when/why to use the scope resolution operator?

So what precisely is the line inside vector<T>

typedef ? const_iterator;

[toc] | [prev] | [next] | [standalone]

#37152

Doug Mika <dougmmika@gmail.com> wrote in
news:2f529752-4a8f-448f-a0e1-309b5ea7b88a@googlegroups.com: 

> So what precisely is the line inside vector<T>
> 
> typedef ? const_iterator;

http://www.learncpp.com/cpp-tutorial/46-typedefs/

[toc] | [prev] | [next] | [standalone]

#37153

On Friday, 17 July 2015 21:10:20 UTC+3, Doug Mika  wrote:
> On Friday, July 17, 2015 at 11:52:39 AM UTC-5, Doug Mika wrote:
> > Hi to all
> > 
> > I have been reading about C++ for a while, but I must admit, that one of the things that I find confusing is all the instances when you use the scope resolution operator ::.  Namespaces, inheritence, etc...
> > 
> > So it begs the question, when we write vector<int>::const_iterator myIterator
> > can I deduce from this that const_iterator is an inner class of vector<int> class?  Is it?
> > 
> > Does anyone know of a easy to read and comprehensive introduction to how/when/why to use the scope resolution operator?
> 
> So what precisely is the line inside vector<T>
> 
> typedef ? const_iterator;

It is required to be a type that fulfills requirements to random access
iterator to const T. 
http://www.cplusplus.com/reference/iterator/RandomAccessIterator/

What it really is may depend on compiler options. Compiler's 
documentation may specify more about it but usage of such
implementation-specific knowledge results with non-portable code.
 

[toc] | [prev] | [next] | [standalone]

#37151

On Fri, 2015-07-17, Doug Mika wrote:
> Hi to all
>

> I have been reading about C++ for a while, but I must admit, that
> one of the things that I find confusing is all the instances when you
> use the scope resolution operator ::.  Namespaces, inheritence, etc...

> So it begs the question, when we write vector<int>::const_iterator
> myIterator can I deduce from this that const_iterator is an inner
> class of vector<int> class?  Is it?

> Does anyone know of a easy to read and comprehensive introduction to
> how/when/why to use the scope resolution operator?

*Shrug* Call me lazy, but I use :: when I have to; when the compiler
refuses to understand me if I don't. 

For vector<int>::const_iterator it's obvious that I have to; there is
no all-purpose "const_iterator", and I'm not inside the implementation
of vector<int>, so I have to be specific (or use "auto").

/Jorgen

-- 
  // Jorgen Grahn <grahn@  Oo  o.   .     .
\X/     snipabacken.se>   O  o   .

[toc] | [prev] | [next] | [standalone]

#37162

On Fri, 17 Jul 2015 09:52:11 -0700 (PDT), Doug Mika
<dougmmika@gmail.com> wrote:

.. snip ..
>So it begs the question, when we write vector<int>::const_iterator myIterator
>can I deduce from this that const_iterator is an inner class of vector<int> class?  Is it?

To be pedantic, it doesn't *beg* the question, it *raises* the
question.  Hopefully, this link is accessible without a New York Times
subscription:

http://afterdeadline.blogs.nytimes.com/2008/09/25/begging-the-question-again/

That links to this page, which might be helpful:

http://begthequestion.info/

And what's C++ all about, if it's not about being pedantic? :)

Louis

[toc] | [prev] | [next] | [standalone]

#37173

[Please do not mail me a copy of your followup]

Louis Krupp <lkrupp@nospam.pssw.com.invalid> spake the secret code
<6tvmqald55cj4d19qpvq7j2pi4kag4r7a2@4ax.com> thusly:

>And what's C++ all about, if it's not about being pedantic? :)

s/C++/comp.lang.c++/ and I'm in agreement.

A tautology is a thing that is tautological.
-- 
"The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline>
     The Computer Graphics Museum <http://computergraphicsmuseum.org>
         The Terminals Wiki <http://terminals.classiccmp.org>
  Legalize Adulthood! (my blog) <http://legalizeadulthood.wordpress.com>

[toc] | [prev] | [next] | [standalone]

#37176

On 7/20/2015 11:59 AM, Richard wrote:
>
> A tautology is a thing that is tautological.
>

https://xkcd.com/703/

[toc] | [prev] | [standalone]

Back to top | Article view | comp.lang.c++

csiph-web