std::swap(std::priority_queue)

 

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Adaptors

stack

queue

priority_queue

flat_set (C++23)

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span (C++20)

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std::priority_queue

Member functions

priority_queue::priority_queue

priority_queue::~priority_queue

priority_queue::operator=

Element access

priority_queue::top

Capacity

priority_queue::empty

priority_queue::size

Modifiers

priority_queue::push

priority_queue::push_range (C++23)

priority_queue::emplace (C++11)

priority_queue::pop

priority_queue::swap (C++11)

Non-member functions

swap(std::priority_queue) (C++11)

Helper classes

uses_allocator<std::priority_queue> (C++11)

formatter<std::priority_queue> (C++23)

Deduction guides(C++17)

 

Defined in header <queue>
template< class T, class Container, class Compare > void swap( std::priority_queue<T, Container, Compare>& lhs,            std::priority_queue<T, Container, Compare>& rhs );		(since C++11) (until C++17)
template< class T, class Container, class Compare > void swap( std::priority_queue<T, Container, Compare>& lhs,            std::priority_queue<T, Container, Compare>& rhs )                noexcept(/* see below */);		(since C++17)

Specializes the std::swap algorithm for std::priority_queue. Swaps the contents of lhs and rhs. Calls lhs.swap(rhs).

This overload participates in overload resolution only if std::is_swappable_v<Container> and std::is_swappable_v<Compare> are both true.

(since C++17)

Parameters

lhs, rhs

-

containers whose contents to swap

Return value

(none)

Complexity

Same as swapping the underlying containers.

Exceptions

noexcept specification:   noexcept(noexcept(lhs.swap(rhs)))

(since C++17)

Notes

Although the overloads of std::swap for container adaptors are introduced in C++11, container adaptors can already be swapped by std::swap in C++98. Such calls to std::swap usually have linear time complexity, but better complexity may be provided.

Example

Run this code

#include <algorithm>
#include <iostream>
#include <queue>
 
int main()
{
    std::priority_queue<int> alice;
    std::priority_queue<int> bob;
 
    auto print = [](const auto& title, const auto& cont)
    {
        std::cout << title << " size=" << cont.size();
        std::cout << " top=" << cont.top() << '\n';
    };
 
    for (int i = 1; i < 4; ++i)
        alice.push(i);
    for (int i = 7; i < 11; ++i)
        bob.push(i);
 
    // Print state before swap
    print("Alice:", alice);
    print("Bobby:", bob);
 
    std::cout << "-- SWAP\n";
    std::swap(alice, bob);
 
    // Print state after swap
    print("Alice:", alice);
    print("Bobby:", bob);
}

Output:

Alice: size=3 top=3
Bobby: size=4 top=10
-- SWAP
Alice: size=4 top=10
Bobby: size=3 top=3

See also

swap (C++11)

swaps the contents (public member function)