std::multimap<Key,T,Compare,Allocator>::empty
Min standard notice:
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 <map>
#include <utility>
int main()
{
std::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';
}