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tqt3/doc/qvaluestack.doc

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/****************************************************************************
**
** QValueStack class documentation
**
** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the Qt GUI Toolkit.
**
** This file may be used under the terms of the GNU General
** Public License versions 2.0 or 3.0 as published by the Free
** Software Foundation and appearing in the files LICENSE.GPL2
** and LICENSE.GPL3 included in the packaging of this file.
** Alternatively you may (at your option) use any later version
** of the GNU General Public License if such license has been
** publicly approved by Trolltech ASA (or its successors, if any)
** and the KDE Free Qt Foundation.
**
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** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
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** herein.
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**********************************************************************/
/*****************************************************************************
QValueStack documentation
*****************************************************************************/
/*!
\class QValueStack qvaluestack.h
\brief The QValueStack class is a value-based template class that provides a stack.
\ingroup qtl
\ingroup tools
\ingroup shared
\mainclass
\reentrant
Define a template instance QValueStack\<X\> to create a stack of
values that all have the class X. QValueStack is part of the \link
qtl.html Qt Template Library\endlink.
Note that QValueStack does not store pointers to the members of
the stack; it holds a copy of every member. That is why these
kinds of classes are called "value based"; QPtrStack, QPtrList,
QDict, etc., are "pointer based".
A stack is a last in, first out (LIFO) structure. Items are added
to the top of the stack with push() and retrieved from the top
with pop(). The top() function provides access to the topmost item
without removing it.
Example:
\code
QValueStack<int> stack;
stack.push( 1 );
stack.push( 2 );
stack.push( 3 );
while ( ! stack.isEmpty() )
cout << "Item: " << stack.pop() << endl;
// Output:
// Item: 3
// Item: 2
// Item: 1
\endcode
QValueStack is a specialized QValueList provided for convenience.
All of QValueList's functionality also applies to QPtrStack, for
example the facility to iterate over all elements using
QValueStack<T>::Iterator. See QValueListIterator for further
details.
Some classes cannot be used within a QValueStack, for example
everything derived from QObject and thus all classes that
implement widgets. Only values can be used in a QValueStack. To
qualify as a value, the class must provide
\list
\i a copy constructor;
\i an assignment operator;
\i a default constructor, i.e. a constructor that does not take any arguments.
\endlist
Note that C++ defaults to field-by-field assignment operators and
copy constructors if no explicit version is supplied. In many
cases this is sufficient.
*/
/*!
\fn QValueStack::QValueStack()
Constructs an empty stack.
*/
/*!
\fn QValueStack::~QValueStack()
Destroys the stack. References to the values in the stack and all
iterators of this stack become invalidated. Because QValueStack is
highly tuned for performance, you won't see warnings if you use
invalid iterators because it is impossible for an iterator to
check whether or not it is valid.
*/
/*!
\fn void QValueStack::push( const T& d )
Adds element, \a d, to the top of the stack. Last in, first out.
This function is equivalent to append().
\sa pop(), top()
*/
/*!
\fn T& QValueStack::top()
Returns a reference to the top item of the stack or the item
referenced by end() if no such item exists. Note that you must not
change the value the end() iterator points to.
This function is equivalent to last().
\sa pop(), push(), QValueList::fromLast()
*/
/*!
\fn const T& QValueStack::top() const
\overload
Returns a reference to the top item of the stack or the item
referenced by end() if no such item exists.
This function is equivalent to last().
\sa pop(), push(), QValueList::fromLast()
*/
/*!
\fn T QValueStack::pop()
Removes the top item from the stack and returns it.
\sa top() push()
*/