libstdc++
Public Types | Public Member Functions | Protected Attributes | List of all members
std::priority_queue< _Tp, _Sequence, _Compare > Class Template Reference
Sequences

Public Types

typedef _Sequence::const_reference const_reference
 
typedef _Sequence container_type
 
typedef _Sequence::reference reference
 
typedef _Sequence::size_type size_type
 
typedef _Sequence::value_type value_type
 

Public Member Functions

 priority_queue (const _Compare &__x, const _Sequence &__s)
 
 priority_queue (const _Compare &__x=_Compare(), _Sequence &&__s=_Sequence())
 
template<typename _InputIterator >
 priority_queue (_InputIterator __first, _InputIterator __last, const _Compare &__x, const _Sequence &__s)
 
template<typename _InputIterator >
 priority_queue (_InputIterator __first, _InputIterator __last, const _Compare &__x=_Compare(), _Sequence &&__s=_Sequence())
 
template<typename... _Args>
void emplace (_Args &&...__args)
 
bool empty () const
 
void pop ()
 
void push (const value_type &__x)
 
void push (value_type &&__x)
 
size_type size () const
 
void swap (priority_queue &__pq) noexcept(noexcept(swap(c, __pq.c))&&noexcept(swap(comp, __pq.comp)))
 
const_reference top () const
 

Protected Attributes

_Sequence c
 
_Compare comp
 

Detailed Description

template<typename _Tp, typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
class std::priority_queue< _Tp, _Sequence, _Compare >

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.

Note
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?)

Definition at line 361 of file stl_queue.h.

Constructor & Destructor Documentation

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
std::priority_queue< _Tp, _Sequence, _Compare >::priority_queue ( const _Compare &  __x,
const _Sequence &  __s 
)
inlineexplicit

Default constructor creates no elements.

Definition at line 396 of file stl_queue.h.

References std::make_heap().

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
template<typename _InputIterator >
std::priority_queue< _Tp, _Sequence, _Compare >::priority_queue ( _InputIterator  __first,
_InputIterator  __last,
const _Compare &  __x,
const _Sequence &  __s 
)
inline

Builds a queue from a range.

Parameters
__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 436 of file stl_queue.h.

References std::make_heap().

Member Function Documentation

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
bool std::priority_queue< _Tp, _Sequence, _Compare >::empty ( ) const
inline

Returns true if the queue is empty.

Definition at line 462 of file stl_queue.h.

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
void std::priority_queue< _Tp, _Sequence, _Compare >::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 525 of file stl_queue.h.

References std::pop_heap().

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
void std::priority_queue< _Tp, _Sequence, _Compare >::push ( const value_type &  __x)
inline

Add data to the queue.

Parameters
__xData to be added.

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

Definition at line 490 of file stl_queue.h.

References std::push_heap().

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
size_type std::priority_queue< _Tp, _Sequence, _Compare >::size ( ) const
inline

Returns the number of elements in the queue.

Definition at line 467 of file stl_queue.h.

template<typename _Tp , typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
const_reference std::priority_queue< _Tp, _Sequence, _Compare >::top ( ) const
inline

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

Definition at line 475 of file stl_queue.h.

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