A list class

class LinkedList { public: LinkedList(); ~LinkedList(); // destructor needed bool isEmpty(); int length(); void insert(int position, Item item); Item delete(int position); Item get(int position); private: ListNode * head; };

Notice that there isn't anything profoundly different about this definition. The difference is simply that the language gives us direct support for the concept that was implicit in the C-style ADT.

Variations on the list

• It can be useful to have "housekeeping" information in the the list class:

  private: int length; Node *head, *last;

• One can use an entire dummy node as the head, rather than simply a pointer:

  private: Node head;

  This can eliminate some special cases in the insert/delete code. Often the memory overhead of having a node instead of a pointer is negligible.

• The list type we have defined uses "internal" data for its nodes. Often one defines "external" data instead:

  class ListNode { Item * element; // store only a pointer ListNode * next; };