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; }; }
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 reference operator*() const;
constexpr pointer operator->() const
requires (is_pointer_v<Iterator> ||
requires (const Iterator i) { i.operator->(); });
constexpr unspecified operator[](difference_type n) const;
template<class Iterator1, class Iterator2>
constexpr bool operator==(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr bool operator!=(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr bool operator<(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr bool operator>(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr bool operator<=(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr bool operator>=(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y);
template<class Iterator1, class Iterator2>
constexpr auto operator-(
const reverse_iterator<Iterator1>& x,
const reverse_iterator<Iterator2>& y) -> decltype(y.base() - x.base());
template<class Iterator>
constexpr reverse_iterator<Iterator> operator+(
typename reverse_iterator<Iterator>::difference_type n,
const reverse_iterator<Iterator>& x);
friend constexpr iter_rvalue_reference_t<Iterator>
iter_move(const reverse_iterator& i) noexcept(see below);
is_nothrow_copy_constructible_v<Iterator> && noexcept(ranges::iter_move(--declval<Iterator&>()))
template<indirectly_swappable<Iterator> Iterator2>
friend constexpr void
iter_swap(const reverse_iterator& x,
const reverse_iterator<Iterator2>& y) noexcept(see below);
auto xtmp = x.base(); auto ytmp = y.base(); ranges::iter_swap(--xtmp, --ytmp);
is_nothrow_copy_constructible_v<Iterator> && is_nothrow_copy_constructible_v<Iterator2> && noexcept(ranges::iter_swap(--declval<Iterator&>(), --declval<Iterator2&>()))
template<class Iterator>
constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i);
while (first != last) *result++ = *first++;causes a range [first, last) to be copied into a range starting with result.
namespace std { template<class Container> class back_insert_iterator { protected: Container* container = nullptr; public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using container_type = Container; constexpr back_insert_iterator() noexcept = default; constexpr explicit back_insert_iterator(Container& x); constexpr back_insert_iterator& operator=(const typename Container::value_type& value); constexpr back_insert_iterator& operator=(typename Container::value_type&& value); constexpr back_insert_iterator& operator*(); constexpr back_insert_iterator& operator++(); constexpr back_insert_iterator operator++(int); }; }
constexpr explicit back_insert_iterator(Container& x);
constexpr back_insert_iterator& operator=(const typename Container::value_type& value);
constexpr back_insert_iterator& operator=(typename Container::value_type&& value);
constexpr back_insert_iterator& operator*();
constexpr back_insert_iterator& operator++();
constexpr back_insert_iterator operator++(int);
template<class Container>
constexpr back_insert_iterator<Container> back_inserter(Container& x);
namespace std { template<class Container> class front_insert_iterator { protected: Container* container = nullptr; public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using container_type = Container; constexpr front_insert_iterator() noexcept = default; constexpr explicit front_insert_iterator(Container& x); constexpr front_insert_iterator& operator=(const typename Container::value_type& value); constexpr front_insert_iterator& operator=(typename Container::value_type&& value); constexpr front_insert_iterator& operator*(); constexpr front_insert_iterator& operator++(); constexpr front_insert_iterator operator++(int); }; }
constexpr explicit front_insert_iterator(Container& x);
constexpr front_insert_iterator& operator=(const typename Container::value_type& value);
constexpr front_insert_iterator& operator=(typename Container::value_type&& value);
constexpr front_insert_iterator& operator*();
constexpr front_insert_iterator& operator++();
constexpr front_insert_iterator operator++(int);
template<class Container>
constexpr front_insert_iterator<Container> front_inserter(Container& x);
namespace std { template<class Container> class insert_iterator { protected: Container* container = nullptr; ranges::iterator_t<Container> iter = ranges::iterator_t<Container>(); public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using container_type = Container; insert_iterator() = default; constexpr insert_iterator(Container& x, ranges::iterator_t<Container> i); constexpr insert_iterator& operator=(const typename Container::value_type& value); constexpr insert_iterator& operator=(typename Container::value_type&& value); constexpr insert_iterator& operator*(); constexpr insert_iterator& operator++(); constexpr insert_iterator& operator++(int); }; }
constexpr insert_iterator(Container& x, ranges::iterator_t<Container> i);
constexpr insert_iterator& operator=(const typename Container::value_type& value);
constexpr insert_iterator& operator=(typename Container::value_type&& value);
constexpr insert_iterator& operator*();
constexpr insert_iterator& operator++();
constexpr insert_iterator& operator++(int);
template<class Container>
constexpr insert_iterator<Container>
inserter(Container& x, ranges::iterator_t<Container> i);
list<string> s; // populate the list s vector<string> v1(s.begin(), s.end()); // copies strings into v1 vector<string> v2(make_move_iterator(s.begin()), make_move_iterator(s.end())); // moves strings into v2β end example
namespace std { template<class Iterator> class move_iterator { public: using iterator_type = Iterator; using iterator_concept = input_iterator_tag; using iterator_category = see below; using value_type = iter_value_t<Iterator>; using difference_type = iter_difference_t<Iterator>; using pointer = Iterator; using reference = iter_rvalue_reference_t<Iterator>; 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 iterator_type base() &&; constexpr reference operator*() const; constexpr move_iterator& operator++(); constexpr auto 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 reference operator[](difference_type n) const; template<sentinel_for<Iterator> S> friend constexpr bool operator==(const move_iterator& x, const move_sentinel<S>& y); template<sized_sentinel_for<Iterator> S> friend constexpr iter_difference_t<Iterator> operator-(const move_sentinel<S>& x, const move_iterator& y); template<sized_sentinel_for<Iterator> S> friend constexpr iter_difference_t<Iterator> operator-(const move_iterator& x, const move_sentinel<S>& y); friend constexpr iter_rvalue_reference_t<Iterator> iter_move(const move_iterator& i) noexcept(noexcept(ranges::iter_move(i.current))); template<indirectly_swappable<Iterator> Iterator2> friend constexpr void iter_swap(const move_iterator& x, const move_iterator<Iterator2>& y) noexcept(noexcept(ranges::iter_swap(x.current, y.current))); private: Iterator current; // exposition only }; }
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 base() const &;
constexpr Iterator base() &&;
constexpr reference operator*() const;
constexpr reference operator[](difference_type n) const;
template<class Iterator1, class Iterator2>
constexpr bool operator==(const move_iterator<Iterator1>& x,
const move_iterator<Iterator2>& y);
template<sentinel_for<Iterator> S>
friend constexpr bool operator==(const move_iterator& x,
const move_sentinel<S>& 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<sized_sentinel_for<Iterator> S>
friend constexpr iter_difference_t<Iterator>
operator-(const move_sentinel<S>& x, const move_iterator& y);
template<sized_sentinel_for<Iterator> S>
friend constexpr iter_difference_t<Iterator>
operator-(const move_iterator& x, const move_sentinel<S>& y);
template<class Iterator>
constexpr move_iterator<Iterator>
operator+(iter_difference_t<Iterator> n, const move_iterator<Iterator>& x);
friend constexpr iter_rvalue_reference_t<Iterator>
iter_move(const move_iterator& i)
noexcept(noexcept(ranges::iter_move(i.current)));
template<indirectly_swappable<Iterator> Iterator2>
friend constexpr void
iter_swap(const move_iterator& x, const move_iterator<Iterator2>& y)
noexcept(noexcept(ranges::iter_swap(x.current, y.current)));
template<class Iterator>
constexpr move_iterator<Iterator> make_move_iterator(Iterator i);
template<input_iterator I, sentinel_for<I> S, weakly_incrementable O, indirect_unary_predicate<I> Pred> requires indirectly_movable<I, O> void move_if(I first, S last, O out, Pred pred) { std::ranges::copy_if(move_iterator<I>{first}, move_sentinel<S>{last}, out, pred); }β end example
namespace std { template<semiregular S> class move_sentinel { public: constexpr move_sentinel(); constexpr explicit move_sentinel(S s); template<class S2> requires convertible_to<const S2&, S> constexpr move_sentinel(const move_sentinel<S2>& s); template<class S2> requires assignable_from<S&, const S2&> constexpr move_sentinel& operator=(const move_sentinel<S2>& s); constexpr S base() const; private: S last; // exposition only }; }
constexpr move_sentinel();
constexpr explicit move_sentinel(S s);
template<class S2>
requires convertible_to<const S2&, S>
constexpr move_sentinel(const move_sentinel<S2>& s);
template<class S2>
requires assignable_from<S&, const S2&>
constexpr move_sentinel& operator=(const move_sentinel<S2>& s);
constexpr S base() const;
template<class ForwardIterator> void fun(ForwardIterator begin, ForwardIterator end); list<int> s; // populate the list s using CI = common_iterator<counted_iterator<list<int>::iterator>, default_sentinel_t>; // call fun on a range of 10 ints fun(CI(counted_iterator(s.begin(), 10)), CI(default_sentinel));β end example
namespace std { template<input_or_output_iterator I, sentinel_for<I> S> requires (!same_as<I, S> && copyable<I>) class common_iterator { public: constexpr common_iterator() = default; constexpr common_iterator(I i); constexpr common_iterator(S s); template<class I2, class S2> requires convertible_to<const I2&, I> && convertible_to<const S2&, S> constexpr common_iterator(const common_iterator<I2, S2>& x); template<class I2, class S2> requires convertible_to<const I2&, I> && convertible_to<const S2&, S> && assignable_from<I&, const I2&> && assignable_from<S&, const S2&> common_iterator& operator=(const common_iterator<I2, S2>& x); decltype(auto) operator*(); decltype(auto) operator*() const requires dereferenceable<const I>; decltype(auto) operator->() const requires see below; common_iterator& operator++(); decltype(auto) operator++(int); template<class I2, sentinel_for<I> S2> requires sentinel_for<S, I2> friend bool operator==( const common_iterator& x, const common_iterator<I2, S2>& y); template<class I2, sentinel_for<I> S2> requires sentinel_for<S, I2> && equality_comparable_with<I, I2> friend bool operator==( const common_iterator& x, const common_iterator<I2, S2>& y); template<sized_sentinel_for<I> I2, sized_sentinel_for<I> S2> requires sized_sentinel_for<S, I2> friend iter_difference_t<I2> operator-( const common_iterator& x, const common_iterator<I2, S2>& y); friend iter_rvalue_reference_t<I> iter_move(const common_iterator& i) noexcept(noexcept(ranges::iter_move(declval<const I&>()))) requires input_iterator<I>; template<indirectly_swappable<I> I2, class S2> friend void iter_swap(const common_iterator& x, const common_iterator<I2, S2>& y) noexcept(noexcept(ranges::iter_swap(declval<const I&>(), declval<const I2&>()))); private: variant<I, S> v_; // exposition only }; template<class I, class S> struct incrementable_traits<common_iterator<I, S>> { using difference_type = iter_difference_t<I>; }; template<input_iterator I, class S> struct iterator_traits<common_iterator<I, S>> { using iterator_concept = see below; using iterator_category = see below; using value_type = iter_value_t<I>; using difference_type = iter_difference_t<I>; using pointer = see below; using reference = iter_reference_t<I>; }; }
constexpr common_iterator(I i);
constexpr common_iterator(S s);
template<class I2, class S2>
requires convertible_to<const I2&, I> && convertible_to<const S2&, S>
constexpr common_iterator(const common_iterator<I2, S2>& x);
template<class I2, class S2>
requires convertible_to<const I2&, I> && convertible_to<const S2&, S> &&
assignable_from<I&, const I2&> && assignable_from<S&, const S2&>
common_iterator& operator=(const common_iterator<I2, S2>& x);
decltype(auto) operator->() const
requires see below;
auto&& tmp = *get<I>(v_); return addressof(tmp);
class proxy { iter_value_t<I> keep_; proxy(iter_reference_t<I>&& x) : keep_(std::move(x)) {} public: const iter_value_t<I>* operator->() const { return addressof(keep_); } };
template<class I2, sentinel_for<I> S2>
requires sentinel_for<S, I2>
friend bool operator==(
const common_iterator& x, const common_iterator<I2, S2>& y);
template<class I2, sentinel_for<I> S2>
requires sentinel_for<S, I2> && equality_comparable_with<I, I2>
friend bool operator==(
const common_iterator& x, const common_iterator<I2, S2>& y);
template<sized_sentinel_for<I> I2, sized_sentinel_for<I> S2>
requires sized_sentinel_for<S, I2>
friend iter_difference_t<I2> operator-(
const common_iterator& x, const common_iterator<I2, S2>& y);
friend iter_rvalue_reference_t<I> iter_move(const common_iterator& i)
noexcept(noexcept(ranges::iter_move(declval<const I&>())))
requires input_iterator<I>;
namespace std {
struct default_sentinel_t { };
}
list<string> s; // populate the list s with at least 10 strings vector<string> v; // copies 10 strings into v: ranges::copy(counted_iterator(s.begin(), 10), default_sentinel, back_inserter(v));β end example
namespace std { template<input_or_output_iterator I> class counted_iterator { public: using iterator_type = I; constexpr counted_iterator() = default; constexpr counted_iterator(I x, iter_difference_t<I> n); template<class I2> requires convertible_to<const I2&, I> constexpr counted_iterator(const counted_iterator<I2>& x); template<class I2> requires assignable_from<I&, const I2&> constexpr counted_iterator& operator=(const counted_iterator<I2>& x); constexpr I base() const & requires copy_constructible<I>; constexpr I base() &&; constexpr iter_difference_t<I> count() const noexcept; constexpr decltype(auto) operator*(); constexpr decltype(auto) operator*() const requires dereferenceable<const I>; constexpr counted_iterator& operator++(); decltype(auto) operator++(int); constexpr counted_iterator operator++(int) requires forward_iterator<I>; constexpr counted_iterator& operator--() requires bidirectional_iterator<I>; constexpr counted_iterator operator--(int) requires bidirectional_iterator<I>; constexpr counted_iterator operator+(iter_difference_t<I> n) const requires random_access_iterator<I>; friend constexpr counted_iterator operator+( iter_difference_t<I> n, const counted_iterator& x) requires random_access_iterator<I>; constexpr counted_iterator& operator+=(iter_difference_t<I> n) requires random_access_iterator<I>; constexpr counted_iterator operator-(iter_difference_t<I> n) const requires random_access_iterator<I>; template<common_with<I> I2> friend constexpr iter_difference_t<I2> operator-( const counted_iterator& x, const counted_iterator<I2>& y); friend constexpr iter_difference_t<I> operator-( const counted_iterator& x, default_sentinel_t); friend constexpr iter_difference_t<I> operator-( default_sentinel_t, const counted_iterator& y); constexpr counted_iterator& operator-=(iter_difference_t<I> n) requires random_access_iterator<I>; constexpr decltype(auto) operator[](iter_difference_t<I> n) const requires random_access_iterator<I>; template<common_with<I> I2> friend constexpr bool operator==( const counted_iterator& x, const counted_iterator<I2>& y); friend constexpr bool operator==( const counted_iterator& x, default_sentinel_t); template<common_with<I> I2> friend constexpr strong_ordering operator<=>( const counted_iterator& x, const counted_iterator<I2>& y); friend constexpr iter_rvalue_reference_t<I> iter_move(const counted_iterator& i) noexcept(noexcept(ranges::iter_move(i.current))) requires input_iterator<I>; template<indirectly_swappable<I> I2> friend constexpr void iter_swap(const counted_iterator& x, const counted_iterator<I2>& y) noexcept(noexcept(ranges::iter_swap(x.current, y.current))); private: I current = I(); // exposition only iter_difference_t<I> length = 0; // exposition only }; template<class I> struct incrementable_traits<counted_iterator<I>> { using difference_type = iter_difference_t<I>; }; template<input_iterator I> struct iterator_traits<counted_iterator<I>> : iterator_traits<I> { using pointer = void; }; }
constexpr counted_iterator(I i, iter_difference_t<I> n);
template<class I2>
requires convertible_to<const I2&, I>
constexpr counted_iterator(const counted_iterator<I2>& x);
constexpr I base() const & requires copy_constructible<I>;
constexpr I base() &&;
constexpr iter_difference_t<I> count() const noexcept;
constexpr decltype(auto) operator*();
constexpr decltype(auto) operator*() const
requires dereferenceable<const I>;
template<common_with<I> I2>
friend constexpr bool operator==(
const counted_iterator& x, const counted_iterator<I2>& y);
friend constexpr bool operator==(
const counted_iterator& x, default_sentinel_t);
template<common_with<I> I2>
friend constexpr strong_ordering operator<=>(
const counted_iterator& x, const counted_iterator<I2>& y);
friend constexpr iter_rvalue_reference_t<I>
iter_move(const counted_iterator& i)
noexcept(noexcept(ranges::iter_move(i.current)))
requires input_iterator<I>;
char* p; // set p to point to a character buffer containing newlines char* nl = find(p, unreachable_sentinel, '\n');
namespace std { struct unreachable_sentinel_t { template<weakly_incrementable I> friend constexpr bool operator==(unreachable_sentinel_t, const I&) noexcept { return false; } }; }