Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Class reference

Posted on 2013-06-13
3
327 Views
Last Modified: 2013-06-28
I have a class defined as follows:
What is the use case of having a reference. it is so confusing :(

class Base
   public:
        class Inner {
              Base& _base;
              public:
                  Inner(Base& in);
         };
};

Base::Inner::Inner(Base& in) 
     : _base(in) {}

Open in new window

0
Comment
Question by:perlperl
  • 2
3 Comments
 
LVL 86

Expert Comment

by:jkr
ID: 39245340
There could be a lot of reasons for such a construct, with the most likely one being to 'link' two specific objects together. Why that is done in your case is quite hard to tell from just that snippet. The must be a reason for 'Inner' to interact with a 'Base' object it is related to.
0
 
LVL 86

Accepted Solution

by:
jkr earned 500 total points
ID: 39245363
BTW, something more basic about references and how they are used: http://en.wikipedia.org/wiki/Reference_%28C%2B%2B%29
0
 
LVL 33

Expert Comment

by:sarabande
ID: 39247053
a reference member needs to be provided at construction time. so, contrary to a pointer member, the object referenced by the member has to exist at construction time of the Inner object (and would need to keep valid thru lifetime of the Inner object).  

as the Inner class is defined within Base class, it is even likely that the Base reference would be a reference to the own parent Base object.

class Base
{
   public:
        class Inner {
              Base& _base;
              public:
                  Inner(Base& in);
         };
        Base();
   private:
       Inner _inner;
};

Base::Inner::Inner(Base& in) 
     : _base(in) {}

Base::Base()
    : _inner(*this) {}

Open in new window


such a construction could be used for to encapsulate all major functionality in the Inner class and to offer only a minimal public interface for the class itself.

Sara
0

Featured Post

Free Tool: ZipGrep

ZipGrep is a utility that can list and search zip (.war, .ear, .jar, etc) archives for text patterns, without the need to extract the archive's contents.

One of a set of tools we're offering as a way to say thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
Go is an acronym of golang, is a programming language developed Google in 2007. Go is a new language that is mostly in the C family, with significant input from Pascal/Modula/Oberon family. Hence Go arisen as low-level language with fast compilation…
The viewer will learn how to user default arguments when defining functions. This method of defining functions will be contrasted with the non-default-argument of defining functions.
The viewer will be introduced to the member functions push_back and pop_back of the vector class. The video will teach the difference between the two as well as how to use each one along with its functionality.

790 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question