Code Fragment: Position

  class Position {                                      // a Position
  private:
    BTPosition btPos;					// position of node
  public:
    Position(const BTPosition &p) : btPos(p) { }	// constructor
    Element& element()  				// get element
      { return btPos.element().element(); }
    const Key& key() const 				// get key (read only)
      { return btPos.element().key(); }
    bool isNull() const 				// a null position?
      { return btPos.isNull(); }
  };