std::priority_queue<T,Container,Compare>::emplace

 

C++

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priority_queue

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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)

 

template< class... Args > void emplace( Args&&... args );		(since C++11)

Pushes a new element to the priority queue. The element is constructed in-place, i.e. no copy or move operations are performed. The constructor of the element is called with exactly the same arguments as supplied to the function.

Effectively calls

c.emplace_back(std::forward<Args>(args)...);
std::push_heap(c.begin(), c.end(), comp);

Parameters

args

-

arguments to forward to the constructor of the element

Return value

(none)

Complexity

Logarithmic number of comparisons plus the complexity of Container::emplace_back.

Example

Run this code

#include <iostream>
#include <queue>
 
struct S
{
    int id;
 
    S(int i, double d, std::string s) : id{i}
    {
        std::cout << "S::S(" << i << ", " << d << ", \"" << s << "\");\n";
    }
    friend bool operator< (S const& x, S const& y) { return x.id < y.id; }
};
 
int main()
{
    std::priority_queue<S> queue;
    queue.emplace(42, 3.14, "C++");
    std::cout << "id: " << queue.top().id << '\n';
}

Output:

S::S(42, 3.14, "C++")
id = 42

See also

push	inserts element and sorts the underlying container (public member function)
pop	removes the top element (public member function)

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