22 Iterators library [iterators]

22.7 Range access [iterator.range]

In addition to being available via inclusion of the <iterator> header, the function templates in [iterator.range] are available when any of the following headers are included: <array>, <deque>, <forward_­list>, <list>, <map>, <regex>, <set>, <span>, <string>, <string_­view>, <unordered_­map>, <unordered_­set>, and <vector>.
Each of these templates is a designated customization point ([namespace.std]).
template<class C> constexpr auto begin(C& c) -> decltype(c.begin()); template<class C> constexpr auto begin(const C& c) -> decltype(c.begin());
Returns: c.begin().
template<class C> constexpr auto end(C& c) -> decltype(c.end()); template<class C> constexpr auto end(const C& c) -> decltype(c.end());
Returns: c.end().
template<class T, size_t N> constexpr T* begin(T (&array)[N]) noexcept;
Returns: array.
template<class T, size_t N> constexpr T* end(T (&array)[N]) noexcept;
Returns: array + N.
template<class C> constexpr auto cbegin(const C& c) noexcept(noexcept(std::begin(c))) -> decltype(std::begin(c));
Returns: std::begin(c).
template<class C> constexpr auto cend(const C& c) noexcept(noexcept(std::end(c))) -> decltype(std::end(c));
Returns: std::end(c).
template<class C> constexpr auto rbegin(C& c) -> decltype(c.rbegin()); template<class C> constexpr auto rbegin(const C& c) -> decltype(c.rbegin());
Returns: c.rbegin().
template<class C> constexpr auto rend(C& c) -> decltype(c.rend()); template<class C> constexpr auto rend(const C& c) -> decltype(c.rend());
Returns: c.rend().
template<class T, size_t N> constexpr reverse_iterator<T*> rbegin(T (&array)[N]);
Returns: reverse_­iterator<T*>(array + N).
template<class T, size_t N> constexpr reverse_iterator<T*> rend(T (&array)[N]);
Returns: reverse_­iterator<T*>(array).
template<class E> constexpr reverse_iterator<const E*> rbegin(initializer_list<E> il);
Returns: reverse_­iterator<const E*>(il.end()).
template<class E> constexpr reverse_iterator<const E*> rend(initializer_list<E> il);
Returns: reverse_­iterator<const E*>(il.begin()).
template<class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));
Returns: std::rbegin(c).
template<class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));
Returns: std::rend(c).