std::forward_list<T,Allocator>::empty - cppreference.com (original) (raw)

| bool empty() const noexcept; | | (since C++11) (constexpr since C++26) | | ---------------------------- | | ------------------------------------- |

Checks if the container has no elements.

[edit] Return value

true if the container is empty, false otherwise.

[edit] Complexity

Constant.

[edit] Example

The following code uses empty to check if a std::forward_list<int> contains any elements:

#include #include   int main() { std::forward_list numbers; std::cout << std::boolalpha; std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';   numbers.push_front(42); numbers.push_front(13317); std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n'; }

Output:

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

[edit] See also

| | returns the distance between two iterators (function template) [edit] | | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |