template <typename> class List; // required forward declaration

template <typename T>
class ListIterator
{

  friend class List<T>;

  public:
    ListIterator();
    bool hasNext() const;
    bool hasPrevious() const;
    T &next(); /* throws NoSuchObject */
    T &previous(); /* throws NoSuchObject */
    void set( const T & ); /* throws NoSuchObject */
    void printInternal() const;

  private:
    Node<T> *current;
    bool before;

}; // ListIterator class