Nested classes

[AtomicChip]

Aiight... A question involving good 'ole data structs (...and nested classes, as the title there would hint )

Let's say I have a class DoubleLinkedList. Within that class, I have a nested class (Iterator). I want to keep this as close to the STL implementation as possible (this is a lot more for learning than anything else, so please don't ask me why I'm doing it this way instead of just using the STL)...

namespace ds
{
  template< typename T >
  class DoubleLinkedList
  {
    public:
    class Iterator
    {
      // ...

      Iterator operator+( )
      {
        // i need to be able to access the "m_head" element of the parent class here
      }

      // ... other operators here ...
    };

    // all public DoubleLinkedList methods here (push, pop, etc)...

    private:
    struct Node
    {
      Node * m_head;
      Node * m_tail;
      T m_data;
    }

    Node * m_head;
    int m_length;

    friend class Iterator;
  };
}

My problem right now is that I am unable to access the parent class's private element "m_head" from within the Iterator class... One possible solution that I have come across is to change the Iterator class to a private member, set a public DoubleLinkedList element of type Iterator, passing it the m_head element in the constructor, but as I said, I want to keep this as close to the STL implementation as possible. In other words (in code), DoubleLinkedList< int >::Iterator.

Is there a keyword to access a parent classes' elements? Am I going about this the wrong way? I've looked a bunch on Google and have been unable to find much about implementing your own iterators... Just a lot 'o stuff about how to use the STL's iterators.

Thanks in advance,

-----------------------------------------------
"The night sky over the planet Krikkit is the least interesting sight in the entire universe."
-Hitch Hiker's Guide To The Galaxy

 

[cpjust]

Maybe

friend class Iterator;

should be:

friend class ds::DoubleLinkedList<T>::Iterator;

Also, what if you tried making the Iterator a separate class instead of nested?

 

[ArkM]

Some addition: in C++ nested class has no special rights to access its parent members. The only effect of nesting is nested class name visibility.
So I think cpjust's advice (with friend keyword) is the only way to go...