Code Fragment: Node



  struct Node {						// node in the NodeList
    Object  element;					// element
    Node*   prev;					// previous node
    Node*   next;					// next node
    Node(const Object& e = Object(), Node* p = NULL, Node* n = NULL)
        : element(e), prev(p), next(n) { }      	// constructor
  };
  typedef Node* NodePtr;				// pointer to a Node