Re: class-object member access in aggregation difficult: please suggest alternatives to aggregation

From: Karl Heinz Buchegger (kbuchegg_at_gascad.at)
Date: 04/22/04 

Date: Thu, 22 Apr 2004 18:13:40 +0200

Chris K wrote:
>
> Hi,
>
> I have used composition to define a class that contains an array
> of classes.
>
> class Ensemble{
> private:
> ElementClass **elements;
>
> public:
> some methods ...
> }
>
> class ElementClass{
> private:
> some members;
>
> public:
> some methods ...
> }
>
> In the constructor I define an array of elements and everything
> works fine.
>
> However, I have come to realize that accessing private members of
> elements in methods belonging to Ensemble is a pain and I do actually
> need to do that.
>
> It seems that the only way - except for making everything public - would
> be walk through two layers of getSomething() methods.

There is a third approach:
ElementClass could declare Ensemble to be a friend and thus grant
Ensemble the right to access private members.

class ElementClass {
  friend class Ensemble;
  private:
    some members;

  public:
    some members;
}; 

-- 
Karl Heinz Buchegger
kbuchegg@gascad.at

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