std::ranges::bidirectional_range

Since C++20

Header: <ranges>

The bidirectional_range concept is a refinement of range for which ranges::begin returns a model of bidirectional_iterator.

# Declarations

template< class T >
concept bidirectional_range =
ranges::forward_range<T> && std::bidirectional_iterator<ranges::iterator_t<T>>;

(since C++20)

# Example

#include <forward_list>
#include <list>
#include <ranges>
#include <set>
#include <unordered_set>
 
int main()
{
    static_assert(
            std::ranges::bidirectional_range<std::set<int>> and
        not std::ranges::bidirectional_range<std::unordered_set<int>> and
            std::ranges::bidirectional_range<std::list<int>> and
        not std::ranges::bidirectional_range<std::forward_list<int>>
    );
}

# See also