std::unordered_multimap<Key,T,Hash,KeyEqual,Allocator>::empty

Since C++11

Checks if the container has no elements, i.e. whether begin() == end().

# Declarations

bool empty() const noexcept;

(since C++11)

# Return value

true if the container is empty, false otherwise.

# Example

#include <iostream>
#include <unordered_map>
#include <utility>
 
int main()
{
    std::unordered_multimap<int,int> numbers;
    std::cout << std::boolalpha;
    std::cout << "Initially, numbers.empty(): " << numbers.empty() << '\n';
 
    numbers.emplace(42, 13);
    numbers.insert(std::make_pair(13317, 123));
    std::cout << "After adding elements, numbers.empty(): " << numbers.empty() << '\n';
}

# See also