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/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the documentation of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain
** additional rights. These rights are described in the Nokia Qt LGPL
** Exception version 1.1, included in the file LGPL_EXCEPTION.txt in this
** package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
/*!
\class QPair
\brief The QPair class is a template class that stores a pair of items.
\ingroup tools
QPair\<T1, T2\> can be used in your application if the STL \c
pair type is not available. It stores one value of type T1 and
one value of type T2. It can be used as a return value for a
function that needs to return two values, or as the value type of
a \l{generic container}.
Here's an example of a QPair that stores one QString and one \c
double value:
\snippet doc/src/snippets/code/doc_src_qpair.qdoc 0
The components are accessible as public data members called \l
first and \l second. For example:
\snippet doc/src/snippets/code/doc_src_qpair.qdoc 1
QPair's template data types (T1 and T2) must be \l{assignable
data types}. You cannot, for example, store a QWidget as a value;
instead, store a QWidget *. A few functions have additional
requirements; these requirements are documented on a per-function
basis.
\sa {Generic Containers}
*/
/*! \typedef QPair::first_type
The type of the first element in the pair (T1).
\sa first
*/
/*! \typedef QPair::second_type
The type of the second element in the pair (T2).
\sa second
*/
/*! \variable QPair::first
The first element in the pair.
*/
/*! \variable QPair::second
The second element in the pair.
*/
/*! \fn QPair::QPair()
Constructs an empty pair. The \c first and \c second elements are
initialized with \l{default-constructed values}.
*/
/*!
\fn QPair::QPair(const T1 &value1, const T2 &value2)
Constructs a pair and initializes the \c first element with \a
value1 and the \c second element with \a value2.
\sa qMakePair()
*/
/*!
\fn QPair<T1, T2> &QPair::operator=(const QPair<T1, T2> &other)
Assigns \a other to this pair.
*/
/*! \fn bool operator==(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is equal to \a p2; otherwise returns false.
Two pairs compare equal if their \c first data members compare
equal and if their \c second data members compare equal.
This function requires the T1 and T2 types to have an
implementation of \c operator==().
*/
/*! \fn bool operator!=(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is not equal to \a p2; otherwise returns
false. Two pairs compare as not equal if their \c first data
members are not equal or if their \c second data members are not
equal.
This function requires the T1 and T2 types to have an
implementation of \c operator==().
*/
/*! \fn bool operator<(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is less than \a p2; otherwise returns
false. The comparison is done on the \c first members of \a p1
and \a p2; if they compare equal, the \c second members are
compared to break the tie.
This function requires the T1 and T2 types to have an
implementation of \c operator<().
*/
/*! \fn bool operator>(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is greater than \a p2; otherwise returns
false. The comparison is done on the \c first members of \a p1
and \a p2; if they compare equal, the \c second members are
compared to break the tie.
This function requires the T1 and T2 types to have an
implementation of \c operator<().
*/
/*! \fn bool operator<=(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is less than or equal to \a p2; otherwise
returns false. The comparison is done on the \c first members of
\a p1 and \a p2; if they compare equal, the \c second members are
compared to break the tie.
This function requires the T1 and T2 types to have an
implementation of \c operator<().
*/
/*! \fn bool operator>=(const QPair<T1, T2> &p1, const QPair<T1, T2> &p2)
\relates QPair
Returns true if \a p1 is greater than or equal to \a p2;
otherwise returns false. The comparison is done on the \c first
members of \a p1 and \a p2; if they compare equal, the \c second
members are compared to break the tie.
This function requires the T1 and T2 types to have an
implementation of \c operator<().
*/
/*!
\fn QPair<T1, T2> qMakePair(const T1 &value1, const T2 &value2)
\relates QPair
Returns a QPair\<T1, T2\> that contains \a value1 and \a value2.
Example:
\snippet doc/src/snippets/code/doc_src_qpair.qdoc 2
This is equivalent to QPair<T1, T2>(\a value1, \a value2), but
usually requires less typing.
*/
/*! \fn QDataStream &operator>>(QDataStream &in, QPair<T1, T2> &pair)
\relates QPair
Reads a pair from stream \a in into \a pair.
This function requires the T1 and T2 types to implement \c operator>>().
\sa {Format of the QDataStream operators}
*/
/*! \fn QDataStream &operator<<(QDataStream &out, const QPair<T1, T2> &pair)
\relates QPair
Writes the pair \a pair to stream \a out.
This function requires the T1 and T2 types to implement \c operator<<().
\sa {Format of the QDataStream operators}
*/
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