//
//   This file contains the C# code from Program 6.23 of
//   "Data Structures and Algorithms
//    with Object-Oriented Design Patterns in C#"
//   by Bruno R. Preiss.
//
//   Copyright (c) 2001--2002 by Bruno R. Preiss, P.Eng.  All rights reserved.
//
//   http://www.brpreiss.com/books/opus6/programs/pgm06_23.txt
//
public class DequeAsArray : QueueAsArray, Deque
{
    public object Tail
    {
	get
	{
	    if (count == 0)
		throw new ContainerEmptyException();
	    return array[tail];
	}
    }

    public void EnqueueTail(object obj)
	{ Enqueue(obj); }

    public object DequeueTail()
    {
	if (count == 0)
	    throw new ContainerEmptyException();
	object result = array[tail];
	array[tail] = null;
	if (tail-- == 0)
	    tail = array.Length - 1;
	--count;
	return result;
    }
    // ...
}