C++

Reference

<queue>

priority_queue

public member function
<queue>

std::priority_queue::empty

bool empty() const;
Test whether container is empty
Returns whether the priority_queue is empty: i.e. whether its size is zero.

This member function effectively calls member empty of the underlying container object.

Parameters

none

Return Value

true if the underlying container's size is 0, false otherwise.

Example

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// priority_queue::empty
#include <iostream>       // std::cout
#include <queue>          // std::priority_queue

int main ()
{
  std::priority_queue<int> mypq;
  int sum (0);

  for (int i=1;i<=10;i++) mypq.push(i);

  while (!mypq.empty())
  {
     sum += mypq.top();
     mypq.pop();
  }

  std::cout << "total: " << sum << '\n';

  return 0;
}
The example initializes the content of the priority queue to a sequence of numbers (form 1 to 10). It then pops the elements one by one until it is empty and calculates their sum.

Output:
total: 55


Complexity

Constant (calling empty on the underlying container).

Data races

The container is accessed.

Exception safety

Provides the same level of guarantees as the operation performed on the container (no-throw guarantee for standard container types).

See also

priority_queue::size
Return size (public member function)