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

From cppreference.com

[edit template]
 
 
 
 
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

#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

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