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/*!

  \class Q3PtrStack

  \brief The Q3PtrStack class is a template class that provides a stack.

  \compat

  Q3ValueStack is an STL-compatible alternative to this class.

  Define a template instance Q3PtrStack\<X\> to create a stack that

  operates on pointers to X, (X*). 

  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(). Use top() to get a reference to the top element

  without changing the stack.

  You can control the stack's deletion policy with setAutoDelete().

  For compatibility with the Q3PtrCollection classes current() and

  remove() are provided; they both operate on the top().

  \sa Q3PtrList Q3PtrQueue

*/

/*!

  \fn Q3PtrStack::Q3PtrStack () 

  Creates an empty stack.

*/

/*!

  \fn Q3PtrStack::Q3PtrStack (const Q3PtrStack<type>& s) 

  Creates a stack by making a shallow copy of another stack \a s.

*/

/*!

  \fn Q3PtrStack::~Q3PtrStack () 

  Destroys the stack. All items will be deleted if autoDelete() is

  true.

*/

/*!

  \fn Q3PtrStack<type>& Q3PtrStack::operator= (const Q3PtrStack<type>& s) 

  Sets the contents of this stack by making a shallow copy of

  another stack \a s. Elements currently in this stack will be

  deleted if autoDelete() is true.

*/

/*!

  \fn bool Q3PtrStack::isEmpty () const 

  Returns true if the stack contains no elements; otherwise returns

  false.

*/

/*!

  \fn void Q3PtrStack::push (const type* d) 

  Adds an element \a d to the top of the stack. Last in, first out.

*/

/*!

  \fn type* Q3PtrStack::pop () 

  Removes the top item from the stack and returns it. The stack must

  not be empty.

*/

/*!

  \fn bool Q3PtrStack::remove () 

  Removes the top item from the stack and deletes it if autoDelete()

  is true. Returns true if there was an item to pop; otherwise

  returns false.

  \sa clear()

*/

/*!

  \fn void Q3PtrStack::clear()

  Removes all items from the stack, deleting them if autoDelete() is

  true.

  \sa remove()

*/

/*!

  \fn uint Q3PtrStack::count() const

  Returns the number of items in the stack.

  \sa isEmpty()

*/

/*!

  \fn type* Q3PtrStack::top () const 

  Returns a pointer to the top item on the stack (most recently

  pushed). The stack is not changed. Returns 0 if the stack is

  empty.

*/

/*!

  \fn Q3PtrStack::operator type* ()const 

  Returns a pointer to the top item on the stack (most recently

  pushed). The stack is not changed. Returns 0 if the stack is

  empty.

*/

/*!

  \fn type* Q3PtrStack::current () const 

  Returns a pointer to the top item on the stack (most recently

  pushed). The stack is not changed. Returns 0 if the stack is

  empty.

*/

/*!

  \fn bool Q3PtrStack::autoDelete() const

  The same as Q3PtrCollection::autoDelete(). Returns true if 

  the auto-delete option is set. If the option is set, the 

  stack auto-deletes its contents. 

  \sa setAutoDelete()

*/

/*!

  \fn void Q3PtrStack::setAutoDelete(bool enable) 

  Defines whether this stack auto-deletes its contents. The same as

  Q3PtrCollection::setAutoDelete(). If \a enable is true, auto-delete

  is turned on.

  If auto-deleting is turned on, all the items in the stack are

  deleted when the stack itself is deleted. This is convenient if

  the stack has the only pointers to the items.

  The default setting is false, for safety. If you turn it on, be

  careful about copying the stack, or you might find yourself with

  two stacks deleting the same items.

  Note that the auto-delete setting may also affect other functions in

  subclasses. For example, a subclass that has a remove() function

  will remove the item from its data structure, and if auto-delete is

  enabled, will also delete the item.

  \sa autoDelete()

*/

/*!

  \fn QDataStream& Q3PtrStack::read(QDataStream& s, Q3PtrCollection::Item& item)

  Reads a stack item, \a item, from the stream \a s and returns a

  reference to the stream.

  The default implementation sets \a item to 0.

  \sa write()

*/

/*!

  \fn QDataStream& Q3PtrStack::write(QDataStream& s,

				     Q3PtrCollection::Item item) const

  Writes a stack item, \a item, to the stream \a s and returns a

  reference to the stream.

  The default implementation does nothing.

  \sa read()

*/