24 Iterators library [iterators]

24.5 Iterator adaptors [predef.iterators]

24.5.1 Reverse iterators [reverse.iterators]

24.5.1.2 Class template reverse_iterator [reverse.iterator]

namespace std { template<class Iterator> class reverse_iterator { public: using iterator_type = Iterator; using iterator_concept = see below; using iterator_category = see below; using value_type = iter_value_t<Iterator>; using difference_type = iter_difference_t<Iterator>; using pointer = typename iterator_traits<Iterator>::pointer; using reference = iter_reference_t<Iterator>; constexpr reverse_iterator(); constexpr explicit reverse_iterator(Iterator x); template<class U> constexpr reverse_iterator(const reverse_iterator<U>& u); template<class U> constexpr reverse_iterator& operator=(const reverse_iterator<U>& u); constexpr Iterator base() const; constexpr reference operator*() const; constexpr pointer operator->() const requires see below; constexpr reverse_iterator& operator++(); constexpr reverse_iterator operator++(int); constexpr reverse_iterator& operator--(); constexpr reverse_iterator operator--(int); constexpr reverse_iterator operator+ (difference_type n) const; constexpr reverse_iterator& operator+=(difference_type n); constexpr reverse_iterator operator- (difference_type n) const; constexpr reverse_iterator& operator-=(difference_type n); constexpr unspecified operator[](difference_type n) const; friend constexpr iter_rvalue_reference_t<Iterator> iter_move(const reverse_iterator& i) noexcept(see below); template<indirectly_swappable<Iterator> Iterator2> friend constexpr void iter_swap(const reverse_iterator& x, const reverse_iterator<Iterator2>& y) noexcept(see below); protected: Iterator current; }; }

The member typedef-name iterator_concept denotes

(1.1)
random_access_iterator_tag if Iterator models random_access_iterator, and
(1.2)
bidirectional_iterator_tag otherwise.

The member typedef-name iterator_category denotes

(2.1)
random_access_iterator_tag if the type iterator_traits<Iterator>::iterator_category models derived_from<random_access_iterator_tag>, and
(2.2)
iterator_traits<Iterator>::iterator_category otherwise.