Program defines a linked-list implementation of a deque.
The DequeAsLinkedList class
extends the QueueAsLinkedList class
introduced in Program
and implements the Deque interface defined in Program
.
The QueueAsLinkedList implementation provides
almost all of the required functionality.
Only five of the six methods defined in the Deque interface
need to be implemented.
Program: DequeAsLinkedList class ``Head'' methods.