Custom Iterator in C++

Question

I have a class TContainer that is an aggregate of several stl collections pointers to TItems class.

I need to create an Iterator to traverse the elements in all the

Answer 1

When I did my own iterator (a while ago now) I inherited from std::iterator and specified the type as the first template parameter. Hope that helps.

For forward iterators user forward_iterator_tag rather than input_iterator_tag in the following code.

This class was originally taken from istream_iterator class (and modified for my own use so it may not resemble the istram_iterator any more).

template
class _iterator
         :public std::iterator // Info about iterator
{
    public:
        const T& operator*() const;
        const T* operator->() const;
        __iterator& operator++();
        __iterator operator++(int);
        bool equal(__iterator const& rhs) const;
};

template
inline bool operator==(__iterator const& lhs,__iterator const& rhs)
{
    return lhs.equal(rhs);
}

Check this documentation on iterator tags:
http://www.sgi.com/tech/stl/iterator_tags.html

Having just re-read the information on iterators:
http://www.sgi.com/tech/stl/iterator_traits.html

This is the old way of doing things (iterator_tags) the more modern approach is to set up iterator_traits<> for your iterator to make it fully compatible with the STL.