namespace std {
template <class Iterator>
class move_iterator {
public:
using iterator_type = Iterator;
using iterator_category = typename iterator_traits<Iterator>::iterator_category;
using value_type = typename iterator_traits<Iterator>::value_type;
using difference_type = typename iterator_traits<Iterator>::difference_type;
using pointer = Iterator;
using reference = see below;
constexpr move_iterator();
constexpr explicit move_iterator(Iterator i);
template <class U> constexpr move_iterator(const move_iterator<U>& u);
template <class U> constexpr move_iterator& operator=(const move_iterator<U>& u);
constexpr iterator_type base() const;
constexpr reference operator*() const;
constexpr pointer operator->() const;
constexpr move_iterator& operator++();
constexpr move_iterator operator++(int);
constexpr move_iterator& operator--();
constexpr move_iterator operator--(int);
constexpr move_iterator operator+(difference_type n) const;
constexpr move_iterator& operator+=(difference_type n);
constexpr move_iterator operator-(difference_type n) const;
constexpr move_iterator& operator-=(difference_type n);
constexpr unspecified operator[](difference_type n) const;
private:
Iterator current; };
template <class Iterator1, class Iterator2>
constexpr bool operator==(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr bool operator!=(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr bool operator<(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr bool operator<=(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr bool operator>(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr bool operator>=(
const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y);
template <class Iterator1, class Iterator2>
constexpr auto operator-(
const move_iterator<Iterator1>& x,
const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base());
template <class Iterator>
constexpr move_iterator<Iterator> operator+(
typename move_iterator<Iterator>::difference_type n, const move_iterator<Iterator>& x);
template <class Iterator>
constexpr move_iterator<Iterator> make_move_iterator(Iterator i);
}
Let R denote iterator_traits<Iterator>::reference.
If is_reference_v<R> is true,
the template specialization move_iterator<Iterator> shall define
the nested type named reference as a synonym for
remove_reference_t<R>&&,
otherwise as a synonym for R.