std:: swap (std::priority_queue)

Parameters

Return value

(none)

Complexity

Same as swapping the underlying containers.

Exceptions

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

#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);
}

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

See also