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

 

C++

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Containers library

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stack

queue

priority_queue

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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

std::swap (C++11)

Deduction guides(C++17)

Helper classes

std::uses_allocator (C++11)

 

bool empty() const;		(until C++20)
[[nodiscard]] bool empty() const;		(since C++20)

Checks if the underlying container has no elements, i.e. whether c.empty().

Parameters

(none)

Return value

true if the underlying container is empty, false otherwise

Complexity

Constant

Example

Run this code

#include <algorithm>
#include <iostream>
#include <queue>
 
int main()
{
    std::cout << std::boolalpha;
 
    std::priority_queue<int> container;
 
    std::cout << "Initially, container.empty(): " << container.empty() << '\n';
 
    container.push(42);
    std::cout << "After adding elements, container.empty(): " << container.empty() << '\n';
}

Output:

Initially, container.empty(): true
After adding elements, container.empty(): false

See also

size	returns the number of elements (public member function)