std::flat_multimap<Key,T,Compare,KeyContainer,MappedContainer>::empty - cppreference.com (original) (raw)

| bool empty() const noexcept; | | (since C++23) | | ---------------------------- | | ------------- |

Checks if the underlying containers have no elements. Equivalent to: return begin() == end();.

[edit] Parameters

(none)

[edit] Return value

true if the underlying containers are empty, false otherwise.

[edit] Complexity

Constant.

[edit] Example

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

Output:

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

[edit] See also

| | returns the number of elements (public member function) [edit] | | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | | checks whether the container is empty (function template) [edit] |