std::unordered_multimap<Key,T,Hash,KeyEqual,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::unordered_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] |