////   This file contains the C# code from Program 6.16 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_16.txt//public class QueueAsArray : AbstractContainer, Queue{    protected object[] array;    protected int head;    protected int tail;    public object Head    {	get	{	    if (count == 0)		throw new ContainerEmptyException();	    return array[head];	}    }    public void Enqueue(object obj)    {	if (count == array.Length)	    throw new ContainerFullException();	if (++tail == array.Length)	    tail = 0;	array[tail] = obj;	++count;    }    public object Dequeue()    {	if (count == 0)	    throw new ContainerEmptyException();	object result = array[head];	array[head] = null;	if (++head == array.Length)	    head = 0;	--count;	return result;    }    // ...}