A C++ iterator adapter which wraps and hides an inner iterator and converts the iterated type

Question

Having toyed with this I suspect it isn\'t remotely possible, but I thought I\'d ask the experts. I have the following C++ code:

class IInterface
{
    virtual vo         


        

Answer 1

It really depends on the Container, because the return values of c.Begin() and c.End() are implementation-defined.

If a list of possible Containers is known to MagicIterator, a wrapper class could be used.

template
class MagicIterator
{
    public:
        MagicIterator(std::vector::const_iterator i)
        {
            vector_const_iterator = i;
        }

        // Reimplement similarly for more types.
        MagicIterator(std::vector::iterator i);
        MagicIterator(std::list::const_iterator i);
        MagicIterator(std::list::iterator i);

        // Reimplement operators here...

    private:
        std::vector::const_iterator vector_const_iterator;
        std::vector::iterator       vector_iterator;
        std::list::const_iterator   list_const_iterator;
        std::list::iterator         list_iterator;
};

The easy way would be to use a template which accepts Container's type:

// C++0x
template
class Iterator :
    public T::iterator
{
    using T::iterator::iterator;
};

for(Iterator i = c.begin(); i != c.end(); ++i)
{
    // ...
}

More information here.