QValueStack(3qt)QValueStack(3qt)NAMEQValueStack - Value based template class that provides a
stack
#include <qvaluestack.h>
Inherits QValueList.
Public Members
QValueStack ()
~QValueStack ()
void push ( const T & d )
T pop ()
T& top ()
const T& top () const
DESCRIPTION
The QValueStack class is a value based template class that
provides a stack.
Define a template instance QValueStack<X> to create a
stack of values which all have the class X. Please notice
that QValueStack does not store pointers to the members of
the stack. It holds a copy of every member. That is the
reason why this kind of classes are called "value based"
while QStack, QList and QDict are "reference 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(). Furthermore, top()
provides access to the topmost item without removing it.
Example:
#include <qvaluestack.h>
#include <stdio.h>
void main()
{
QValueStack<int> stack;
stack.push( 1 );
stack.push( 2 );
stack.push( 3 );
while ( !stack.isEmpty() )
printf("pop item %d\n", stack.pop() );
}
Program output:
pop item 3;
pop item 2;
pop item 1;
Technically, QValueStack is a specialized QValueList
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QValueStack(3qt)QValueStack(3qt)
provided for convenience. All of QValueList's
functionality applies also to QStack, for example the
facility to iterate over all elements using
QValueStack<T>::Iterator. See QValueListIterator for
further details.
Some classes can not 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
a copy constructor,
an assignment operator and
a default constructor, i.e. a constructor that does not
take any arguments.
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.
MEMBER FUNCTION DOCUMENTATIONQValueStack::QValueStack ()
Constructs an empty stack.
QValueStack::~QValueStack ()
Destroys the stack. References to the values in the stack
and all iterators of this stack become invalidated. Since
QValueStack is highly tuned for performance you wont see
warnings if you use invalid iterators, because it is
impossible for an iterator to check wether it is valid or
not.
T QValueStack::pop ()
Removes the top item from the stack and returns it.
See also top() and push().
void QValueStack::push ( const T & d )
Adds an element to the top of the stack. Last in, first
out.
This function is equivalent to append()
See also pop() and top().
T& QValueStack::top ()
Returns a reference to the top item of the stack or the
item referenced by end() if no such item exists. Please
note that you may not change the value the end() Iterator
is pointing to.
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QValueStack(3qt)QValueStack(3qt)
This function is equivalent to last().
See also pop(), push() and QValueList::fromLast().
const T& QValueStack::top () const
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().
See also pop(), push() and QValueList::fromLast().
SEE ALSO
http://doc.trolltech.com/qvaluestack.html
http://www.trolltech.com/faq/tech.html
COPYRIGHT
Copyright 1992-2001 Trolltech AS,
http://www.trolltech.com. See the license file included
in the distribution for a complete license statement.
AUTHOR
Generated automatically from the source code.
BUGS
If you find a bug in Qt, please report it as described in
http://doc.trolltech.com/bughowto.html. Good bug reports
make our job much simpler. Thank you.
In case of content or formattting problems with this
manual page, please report them to qt-bugs@trolltech.com.
Please include the name of the manual page
(qvaluestack.3qt) and the Qt version (2.3.1).
Trolltech AS 13 June 2001 3
