NAME¶

std::flat_map::keys - std::flat_map::keys

Synopsis¶

const key_container_type& keys() const noexcept; (since C++23)

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

Parameters¶

(none)

Return value¶

The underlying keys container.

Complexity¶

Constant.

Example¶

// Run this code

#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());
}

Output:¶

[1, 2, 3]

See also¶

values direct access to the underlying values container
(public member function)