std::priority_queue Class Reference

List of all members.

Public Types

Public Member Functions

Protected Attributes

Detailed Description

A standard container automatically sorting its contents.

This is not a true container, but an adaptor. It holds another container, and provides a wrapper interface to that container. The wrapper is what enforces priority-based sorting and queue behavior. Very few of the standard container/sequence interface requirements are met (e.g., iterators).

The second template parameter defines the type of the underlying sequence/container. It defaults to std::vector, but it can be any type that supports front(), push_back, pop_back, and random-access iterators, such as std::deque or an appropriate user-defined type.

The third template parameter supplies the means of making priority comparisons. It defaults to less<value_type> but can be anything defining a strict weak ordering.

Members not found in normal containers are container_type, which is a typedef for the second Sequence parameter, and push, pop, and top, which are standard queue operations.

No equality/comparison operators are provided for priority_queue.
Sorting of the elements takes place as they are added to, and removed from, the priority_queue using the priority_queue's member functions. If you access the elements by other means, and change their data such that the sorting order would be different, the priority_queue will not re-sort the elements for you. (How could it know to do so?)

Constructor & Destructor Documentation

std::priority_queue::priority_queue ( const _Compare &  __x,
const _Sequence &  __s 
) [inline, explicit]

Default constructor creates no elements.

Definition at line 394 of file stl_queue.h.

References std::make_heap().

template<typename _InputIterator >
std::priority_queue::priority_queue ( _InputIterator  __first,
_InputIterator  __last,
const _Compare &  __x,
const _Sequence &  __s 
) [inline]

Builds a queue from a range.

firstAn input iterator.
lastAn input iterator.
xA comparison functor describing a strict weak ordering.
sAn initial sequence with which to start.

Begins by copying s, inserting a copy of the elements from [first,last) into the copy of s, then ordering the copy according to x.

For more information on function objects, see the documentation on functor base classes.

Definition at line 434 of file stl_queue.h.

References std::make_heap().

Member Function Documentation

bool std::priority_queue::empty ( ) const [inline]

Returns true if the queue is empty.

Definition at line 460 of file stl_queue.h.

void std::priority_queue::pop ( ) [inline]

Removes first element.

This is a typical queue operation. It shrinks the queue by one. The time complexity of the operation depends on the underlying sequence.

Note that no data is returned, and if the first element's data is needed, it should be retrieved before pop() is called.

Definition at line 523 of file stl_queue.h.

References std::pop_heap().

void std::priority_queue::push ( const value_type &  __x) [inline]

Add data to the queue.

xData to be added.

This is a typical queue operation. The time complexity of the operation depends on the underlying sequence.

Definition at line 488 of file stl_queue.h.

References std::push_heap().

size_type std::priority_queue::size ( ) const [inline]

Returns the number of elements in the queue.

Definition at line 465 of file stl_queue.h.

const_reference std::priority_queue::top ( ) const [inline]

Returns a read-only (constant) reference to the data at the first element of the queue.

Definition at line 473 of file stl_queue.h.

The documentation for this class was generated from the following file: