std::flat_map<Key,T,Compare,KeyContainer,MappedContainer>::empty

Since C++23

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

# Declarations

bool empty() const noexcept;

(since C++23)

# Return value

true if the underlying containers are empty, false otherwise.

# Example

#include <iostream>
#include <flat_map>
#include <utility>
 
int main()
{
    std::flat_map<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