std::priority_queue< _Tp, _Sequence, _Compare > Class Template Reference
Containers » Sequences

## Public Types

typedef _Sequence::const_reference | const_reference
typedef _Sequence | container_type
typedef _Sequence::reference | reference
typedef _Sequence::size_type | size_type
typedef _Compare | value_compare
typedef _Sequence::value_type | value_type

## Public Member Functions

template<typename _Seq = _Sequence, typename _Requires = typename enable_if<__and_<is_default_constructible<_Compare>, is_default_constructible<_Seq>>::value>::type>
| priority_queue ()
| priority_queue (const _Compare &__x, const _Sequence &__s)
| priority_queue (const _Compare &__x, _Sequence &&__s=_Sequence())
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (const _Alloc &__a)
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (const _Compare &__x, const _Alloc &__a)
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (const _Compare &__x, const _Sequence &__c, const _Alloc &__a)
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (const _Compare &__x, _Sequence &&__c, const _Alloc &__a)
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (const priority_queue &__q, const _Alloc &__a)
template<typename _Alloc , typename _Requires = _Uses<_Alloc>>
| priority_queue (priority_queue &&__q, const _Alloc &__a)
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(__and_<//c++1z or gnu++11 __is_nothrow_swappable< _Sequence >, __is_nothrow_swappable< _Compare > >::value)
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.

Template Parameters

  _Tp | Type of element.
  _Sequence | Type of underlying sequence, defaults to vector<_Tp>.
  _Compare | Comparison function object type, defaults to less<_Sequence::value_type>.

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 423 of file stl_queue.h.

## Constructor & Destructor Documentation

## priority_queue() [1/2]

template<typename _Tp, typename _Sequence = vector<_Tp>, typename _Compare = less<typename _Sequence::value_type>>
template<typename _Seq = _Sequence, typename _Requires = typename enable_if<__and_<is_default_constructible<_Compare>, is_default_constructible<_Seq>>::value>::type>

std::priority_queue< _Tp, _Sequence, _Compare >::priority_queue | ( |  | ) |

inline

Default constructor creates no elements.

Definition at line 473 of file stl_queue.h.

References std::queue< _Tp, _Sequence >::c, and std::make_heap().

## priority_queue() [2/2]

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

  __first | An input iterator.
  __last | An input iterator.
  __x | A comparison functor describing a strict weak ordering.
  __s | An 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 541 of file stl_queue.h.

## Member Function Documentation

## empty()

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 567 of file stl_queue.h.

## pop()

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 630 of file stl_queue.h.

## push()

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

  __x | Data to be added.

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

Definition at line 595 of file stl_queue.h.

References std::queue< _Tp, _Sequence >::push(), and std::push_heap().

## size()

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 572 of file stl_queue.h.

## top()

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 580 of file stl_queue.h.

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

- stl_queue.h