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

Since C++23

Return a constant reference to the adapted keys container. Equivalent to return c.keys;.

# Declarations

const key_container_type& keys() const noexcept;

(since C++23)

# Return value

The underlying keys container.

# Example

#include <flat_map>
#include <print>
#include <type_traits>
#include <vector>
 
int main()
{
    std::flat_map<int, double> adaptor{{1, 1.1}, {2, 2.2}, {3, 3.3}};
 
    // The default keys container is std::vector:
    static_assert(std::is_same_v<decltype(adaptor.keys()), const std::vector<int>&>);
 
    std::println("{}", adaptor.keys());
}

# See also

values