public member function
<forward_list>

std::forward_list::empty

bool empty() const noexcept;
Test whether array is empty
Returns a bool value indicating whether the forward_list container is empty, i.e. whether its size is 0.

This function does not modify the content of the container in any way. To clear the content of an array object, see forward_list::clear.

Parameters

none

Return Value

true if the container size is 0, false otherwise.

Example

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// forward_list::empty
#include <iostream>
#include <forward_list>

int main ()
{
  std::forward_list<int> first;
  std::forward_list<int> second = {20, 40, 80};
  std::cout << "first " << (first.empty() ? "is empty" : "is not empty" ) << std::endl;
  std::cout << "second " << (second.empty() ? "is empty" : "is not empty" ) << std::endl;
  return 0;
}


Output:
first is empty
second is not empty

Complexity

Constant.

Iterator validity

No changes.

Data races

The container is accessed.
No contained elements are accessed: concurrently accessing or modifying them is safe.

Exception safety

No-throw guarantee: this member function never throws exceptions.

See also

  • 997351548 2018-02-20
  • 903691547 2018-02-20
  • 9127171546 2018-02-20
  • 2234751545 2018-02-20
  • 1685381544 2018-02-20
  • 911091543 2018-02-20
  • 9281021542 2018-02-20
  • 632231541 2018-02-20
  • 9751491540 2018-02-20
  • 8333621539 2018-02-20
  • 995001538 2018-02-20
  • 6477441537 2018-02-20
  • 511981536 2018-02-19
  • 2072881535 2018-02-19
  • 6024461534 2018-02-19
  • 7594061533 2018-02-19
  • 9311341532 2018-02-19
  • 4928331531 2018-02-19
  • 38561530 2018-02-19
  • 7776611529 2018-02-19