/******************************************************************************** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.**** This file is part of the QtCore module of the Qt Toolkit.**** This file may be used under the terms of the GNU General Public** License version 2.0 as published by the Free Software Foundation** and appearing in the file LICENSE.GPL included in the packaging of** this file.  Please review the following information to ensure GNU** General Public Licensing requirements will be met:** http://www.trolltech.com/products/qt/opensource.html**** If you are unsure which license is appropriate for your use, please** review the following information:** http://www.trolltech.com/products/qt/licensing.html or contact the** sales department at sales@trolltech.com.**** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.******************************************************************************//*!    \class QQueue    \brief The QQueue class is a generic container that provides a queue.    \ingroup tools    \ingroup shared    \mainclass    \reentrant    QQueue\<T\> is one of Qt's generic \l{container classes}. It    implements a queue data structure for items of a same type.    A queue is a first in, first out (FIFO) structure. Items are    added to the tail of the queue using enqueue() and retrieved from    the head using dequeue(). The head() function provides access to    the head item without removing it.    Example:    \code        QQueue<int> queue;        queue.enqueue(1);        queue.enqueue(2);        queue.enqueue(3);        while (!queue.isEmpty())            cout << queue.dequeue() << endl;    \endcode    The example will output 1, 2, 3 in that order.    QQueue inherits from QList. All of QList's functionality also    applies to QQueue. For example, you can use isEmpty() to test    whether the queue is empty, and you can traverse a QQueue using    QList's iterator classes (for example, QListIterator). But in    addition, QQueue provides three convenience functions that make    it easy to implement FIFO semantics: enqueue(), dequeue(), and    head().    QQueue's value type must be an \l{assignable data type}. This    covers most data types that are commonly used, but the compiler    won't let you, for example, store a QWidget as a value; instead,    store a QWidget *.    \sa QList, QStack*//*!    \fn QQueue::QQueue()    Constructs an empty queue.*//*!    \fn QQueue::~QQueue()    Destroys the queue. References to the values in the queue, and all    iterators over this queue, become invalid.*//*!    \fn void QQueue::enqueue(const T& t)    Adds value \a t to the tail of the queue.    This is the same as QList::append().    \sa dequeue(), head()*//*!    \fn T &QQueue::head()    Returns a reference to the queue's head item. This function    assumes that the queue isn't empty.    This is the same as QList::first().    \sa dequeue(), enqueue(), isEmpty()*//*!    \fn const T &QQueue::head() const    \overload*//*!    \fn T QQueue::dequeue()    Removes the head item in the queue and returns it. This function    assumes that the queue isn't empty.    This is the same as QList::takeFirst().    \sa head(), enqueue(), isEmpty()*/