| // -*- C++ -*- | 
 | //===----------------------------------------------------------------------===// | 
 | // | 
 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. | 
 | // See https://llvm.org/LICENSE.txt for license information. | 
 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception | 
 | // | 
 | //===----------------------------------------------------------------------===// | 
 |  | 
 | #ifndef _LIBCPP_ITERATOR | 
 | #define _LIBCPP_ITERATOR | 
 |  | 
 | /* | 
 |     iterator synopsis | 
 |  | 
 | #include <concepts> | 
 |  | 
 | namespace std | 
 | { | 
 | template<class> struct incrementable_traits;       // since C++20 | 
 | template<class T> | 
 |   using iter_difference_t = see below;             // since C++20 | 
 |  | 
 | template<class> struct indirectly_readable_traits; // since C++20 | 
 | template<class T> | 
 |   using iter_value_t = see below;                  // since C++20 | 
 |  | 
 | template<class Iterator> | 
 | struct iterator_traits; | 
 |  | 
 | template<class T> | 
 |   requires is_object_v<T>                    // since C++20 | 
 | struct iterator_traits<T*>; | 
 |  | 
 | template<dereferenceable T> | 
 |   using iter_reference_t = decltype(*declval<T&>()); | 
 |  | 
 | namespace ranges::inline unspecified { | 
 |     inline constexpr unspecified iter_move = unspecified; // since C++20, nodiscard as an extension | 
 | }} | 
 |  | 
 | template<dereferenceable T> | 
 |   requires ... | 
 | using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // since C++20 | 
 |  | 
 | // [iterator.concepts], iterator concepts | 
 | // [iterator.concept.readable], concept indirectly_readable | 
 | template<class In> | 
 |   concept indirectly_readable = see below;                      // since C++20 | 
 |  | 
 | template<indirectly_readable T> | 
 |   using iter_common_reference_t = | 
 |     common_reference_t<iter_reference_t<T>, iter_value_t<T>&>;  // since C++20 | 
 |  | 
 | // [iterator.concept.writable], concept indirectly_writable | 
 | template<class Out, class T> | 
 |   concept indirectly_writable = see below;                // since C++20 | 
 |  | 
 | // [iterator.concept.winc], concept weakly_incrementable | 
 | template<class I> | 
 |   concept weakly_incrementable = see below;                // since C++20 | 
 |  | 
 | // [iterator.concept.inc], concept incrementable | 
 | template<class I> | 
 |   concept incrementable = see below;                       // since C++20 | 
 |  | 
 | // [iterator.concept.iterator], concept input_or_output_iterator | 
 |   template<class I> | 
 |     concept input_or_output_iterator = see below;          // since C++20 | 
 |  | 
 | // [iterator.concept.sentinel], concept sentinel_for | 
 | template<class S, class I> | 
 |   concept sentinel_for = see below;                        // since C++20 | 
 |  | 
 | // [iterator.concept.sizedsentinel], concept sized_sentinel_for | 
 | template<class S, class I> | 
 |   inline constexpr bool disable_sized_sentinel_for = false; | 
 |  | 
 | template<class S, class I> | 
 |   concept sized_sentinel_for = see below; | 
 |  | 
 | // [iterator.concept.input], concept input_iterator | 
 | template<class I> | 
 |   concept input_iterator = see below;                      // since C++20 | 
 |  | 
 | // [iterator.concept.output], concept output_iterator | 
 | template<class I, class T> | 
 |   concept output_iterator = see below;                     // since C++20 | 
 |  | 
 | // [iterator.concept.forward], concept forward_iterator | 
 | template<class I> | 
 |   concept forward_iterator = see below;                    // since C++20 | 
 |  | 
 | // [iterator.concept.bidir], concept bidirectional_iterator | 
 | template<class I> | 
 |   concept bidirectional_iterator = see below;              // since C++20 | 
 |  | 
 | // [iterator.concept.random.access], concept random_access_iterator | 
 | template<class I> | 
 |   concept random_access_iterator = see below;              // since C++20 | 
 |  | 
 | // [indirectcallable] | 
 | // [indirectcallable.indirectinvocable] | 
 | template<class F, class I> | 
 |   concept indirectly_unary_invocable = see below;          // since C++20 | 
 |  | 
 | template<class F, class I> | 
 |   concept indirectly_regular_unary_invocable = see below;  // since C++20 | 
 |  | 
 | template<class F, class I> | 
 |   concept indirect_unary_predicate = see below;            // since C++20 | 
 |  | 
 | template<class F, class I1, class I2> | 
 |   concept indirect_binary_predicate = see below;           // since C++20 | 
 |  | 
 | template<class F, class I1, class I2 = I1> | 
 |   concept indirect_equivalence_relation = see below;       // since C++20 | 
 |  | 
 | template<class F, class I1, class I2 = I1> | 
 |   concept indirect_strict_weak_order = see below;          // since C++20 | 
 |  | 
 | template<class F, class... Is> | 
 |   using indirect_result_t = see below;                     // since C++20 | 
 |  | 
 | // [projected], projected | 
 | template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj> | 
 |   struct projected;                                        // since C++20 | 
 |  | 
 | template<weakly_incrementable I, indirectly_regular_unary_invocable<I> Proj> | 
 |   struct incrementable_traits<projected<I, Proj>>;         // since C++20 | 
 |  | 
 | // [alg.req.ind.move], concept indirectly_movable | 
 | template<class In, class Out> | 
 |   concept indirectly_movable = see below;                  // since C++20 | 
 |  | 
 | template<class In, class Out> | 
 |   concept indirectly_movable_storable = see below;         // since C++20 | 
 |  | 
 | // [alg.req.ind.swap], concept indirectly_swappable | 
 | template<class I1, class I2 = I1> | 
 |   concept indirectly_swappable = see below;                // since C++20 | 
 |  | 
 | template<class I1, class I2, class R, class P1 = identity, | 
 |          class P2 = identity> | 
 |   concept indirectly_comparable = | 
 |     indirect_binary_predicate<R, projected<I1, P1>, projected<I2, P2>>; // since C++20 | 
 |  | 
 | template<input_or_output_iterator I, sentinel_for<I> S> | 
 |   requires (!same_as<I, S> && copyable<I>) | 
 | class common_iterator;                                     // since C++20 | 
 |  | 
 | template<class Category, class T, class Distance = ptrdiff_t, | 
 |          class Pointer = T*, class Reference = T&> | 
 | struct iterator                                            // deprecated in C++17 | 
 | { | 
 |     typedef T         value_type; | 
 |     typedef Distance  difference_type; | 
 |     typedef Pointer   pointer; | 
 |     typedef Reference reference; | 
 |     typedef Category  iterator_category; | 
 | }; | 
 |  | 
 | struct input_iterator_tag  {}; | 
 | struct output_iterator_tag {}; | 
 | struct forward_iterator_tag       : public input_iterator_tag         {}; | 
 | struct bidirectional_iterator_tag : public forward_iterator_tag       {}; | 
 | struct random_access_iterator_tag : public bidirectional_iterator_tag {}; | 
 |  | 
 | // 27.4.3, iterator operations | 
 | template <class InputIterator, class Distance>  // constexpr in C++17 | 
 |   constexpr void advance(InputIterator& i, Distance n); | 
 |  | 
 | template <class InputIterator>  // constexpr in C++17 | 
 |   constexpr typename iterator_traits<InputIterator>::difference_type | 
 |     distance(InputIterator first, InputIterator last); | 
 |  | 
 | template <class InputIterator>  // constexpr in C++17 | 
 |   constexpr InputIterator next(InputIterator x, | 
 | typename iterator_traits<InputIterator>::difference_type n = 1); | 
 |  | 
 | template <class BidirectionalIterator>  // constexpr in C++17 | 
 |   constexpr BidirectionalIterator prev(BidirectionalIterator x, | 
 |     typename iterator_traits<BidirectionalIterator>::difference_type n = 1); | 
 |  | 
 | // [range.iter.ops], range iterator operations | 
 | namespace ranges { | 
 |   // [range.iter.op.advance], ranges::advance | 
 |   template<input_or_output_iterator I> | 
 |     constexpr void advance(I& i, iter_difference_t<I> n);                          // since C++20 | 
 |   template<input_or_output_iterator I, sentinel_for<I> S> | 
 |     constexpr void advance(I& i, S bound);                                         // since C++20 | 
 |   template<input_or_output_iterator I, sentinel_for<I> S> | 
 |     constexpr iter_difference_t<I> advance(I& i, iter_difference_t<I> n, S bound); // since C++20 | 
 | } | 
 |  | 
 | template <class Iterator> | 
 | class reverse_iterator | 
 |     : public iterator<typename iterator_traits<Iterator>::iterator_category, // until C++17 | 
 |                       typename iterator_traits<Iterator>::value_type, | 
 |                       typename iterator_traits<Iterator>::difference_type, | 
 |                       typename iterator_traits<Iterator>::pointer, | 
 |                       typename iterator_traits<Iterator>::reference> | 
 | { | 
 | protected: | 
 |     Iterator current; | 
 | public: | 
 |     typedef Iterator                                            iterator_type; | 
 |     typedef typename iterator_traits<Iterator>::difference_type difference_type; | 
 |     typedef typename iterator_traits<Iterator>::reference       reference; | 
 |     typedef typename iterator_traits<Iterator>::pointer         pointer; | 
 |  | 
 |     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; | 
 |     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 reference         operator[](difference_type n) const; | 
 | }; | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | operator==(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | operator<(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | operator!=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | operator>(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | operator>=(const reverse_iterator<Iterator1>& x, const reverse_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool                          // constexpr in C++17 | 
 | 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());   // constexpr in C++17 | 
 |  | 
 | template <class Iterator> | 
 | constexpr reverse_iterator<Iterator> | 
 | operator+(typename reverse_iterator<Iterator>::difference_type n, | 
 |           const reverse_iterator<Iterator>& x);   // constexpr in C++17 | 
 |  | 
 | template <class Iterator> | 
 | constexpr reverse_iterator<Iterator> make_reverse_iterator(Iterator i); // C++14, constexpr in C++17 | 
 |  | 
 | template <class Container> | 
 | class back_insert_iterator | 
 |     : public iterator<output_iterator_tag, void, void, void, void> // until C++17 | 
 | { | 
 | protected: | 
 |     Container* container; | 
 | public: | 
 |     typedef Container                   container_type; | 
 |     typedef void                        value_type; | 
 |     typedef void                        difference_type; // until C++20 | 
 |     typedef ptrdiff_t                   difference_type; // since C++20 | 
 |     typedef void                        reference; | 
 |     typedef void                        pointer; | 
 |  | 
 |     explicit back_insert_iterator(Container& x);  // constexpr in C++20 | 
 |     back_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20 | 
 |     back_insert_iterator& operator*();  // constexpr in C++20 | 
 |     back_insert_iterator& operator++();  // constexpr in C++20 | 
 |     back_insert_iterator  operator++(int);  // constexpr in C++20 | 
 | }; | 
 |  | 
 | template <class Container> back_insert_iterator<Container> back_inserter(Container& x);  // constexpr in C++20 | 
 |  | 
 | template <class Container> | 
 | class front_insert_iterator | 
 |     : public iterator<output_iterator_tag, void, void, void, void> // until C++17 | 
 | { | 
 | protected: | 
 |     Container* container; | 
 | public: | 
 |     typedef Container                    container_type; | 
 |     typedef void                         value_type; | 
 |     typedef void                         difference_type; // until C++20 | 
 |     typedef ptrdiff_t                    difference_type; // since C++20 | 
 |     typedef void                         reference; | 
 |     typedef void                         pointer; | 
 |  | 
 |     explicit front_insert_iterator(Container& x);  // constexpr in C++20 | 
 |     front_insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20 | 
 |     front_insert_iterator& operator*();  // constexpr in C++20 | 
 |     front_insert_iterator& operator++();  // constexpr in C++20 | 
 |     front_insert_iterator  operator++(int);  // constexpr in C++20 | 
 | }; | 
 |  | 
 | template <class Container> front_insert_iterator<Container> front_inserter(Container& x);  // constexpr in C++20 | 
 |  | 
 | template <class Container> | 
 | class insert_iterator | 
 |     : public iterator<output_iterator_tag, void, void, void, void> // until C++17 | 
 | { | 
 | protected: | 
 |     Container* container; | 
 |     typename Container::iterator iter; | 
 | public: | 
 |     typedef Container              container_type; | 
 |     typedef void                   value_type; | 
 |     typedef void                   difference_type; // until C++20 | 
 |     typedef ptrdiff_t              difference_type; // since C++20 | 
 |     typedef void                   reference; | 
 |     typedef void                   pointer; | 
 |  | 
 |     insert_iterator(Container& x, typename Container::iterator i);  // constexpr in C++20 | 
 |     insert_iterator& operator=(const typename Container::value_type& value);  // constexpr in C++20 | 
 |     insert_iterator& operator*();  // constexpr in C++20 | 
 |     insert_iterator& operator++();  // constexpr in C++20 | 
 |     insert_iterator& operator++(int);  // constexpr in C++20 | 
 | }; | 
 |  | 
 | template <class Container, class Iterator> | 
 | insert_iterator<Container> inserter(Container& x, Iterator i);  // constexpr in C++20 | 
 |  | 
 | template <class Iterator> | 
 | class move_iterator { | 
 | public: | 
 |     typedef Iterator                                              iterator_type; | 
 |     typedef typename iterator_traits<Iterator>::difference_type   difference_type; | 
 |     typedef Iterator                                              pointer; | 
 |     typedef typename iterator_traits<Iterator>::value_type        value_type; | 
 |     typedef typename iterator_traits<Iterator>::iterator_category iterator_category; | 
 |     typedef value_type&&                                          reference; | 
 |  | 
 |     constexpr move_iterator();  // all the constexprs are in C++17 | 
 |     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; // exposition only | 
 | }; | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator==(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator!=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator<(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator<=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator>(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr bool   // constexpr in C++17 | 
 | operator>=(const move_iterator<Iterator1>& x, const move_iterator<Iterator2>& y); | 
 |  | 
 | template <class Iterator1, class Iterator2> | 
 | constexpr auto   // constexpr in C++17 | 
 | operator-(const move_iterator<Iterator1>& x, | 
 |           const move_iterator<Iterator2>& y) -> decltype(x.base() - y.base()); | 
 |  | 
 | template <class Iterator> | 
 | constexpr move_iterator<Iterator> operator+(   // constexpr in C++17 | 
 |             typename move_iterator<Iterator>::difference_type n, | 
 |             const move_iterator<Iterator>& x); | 
 |  | 
 | template <class Iterator>   // constexpr in C++17 | 
 | constexpr  move_iterator<Iterator> make_move_iterator(const Iterator& i); | 
 |  | 
 | // [default.sentinel], default sentinel | 
 | struct default_sentinel_t; | 
 | inline constexpr default_sentinel_t default_sentinel{}; | 
 |  | 
 | // [iterators.counted], counted iterators | 
 | template<input_or_output_iterator I> class counted_iterator; | 
 |  | 
 | template<input_iterator I> | 
 |   requires see below | 
 |   struct iterator_traits<counted_iterator<I>>; | 
 |  | 
 | // [unreachable.sentinel], unreachable sentinel | 
 | struct unreachable_sentinel_t; | 
 | inline constexpr unreachable_sentinel_t unreachable_sentinel{}; | 
 |  | 
 | template <class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t> | 
 | class istream_iterator | 
 |     : public iterator<input_iterator_tag, T, Distance, const T*, const T&> // until C++17 | 
 | { | 
 | public: | 
 |     typedef input_iterator_tag           iterator_category; | 
 |     typedef T                            value_type; | 
 |     typedef Distance                     difference_type; | 
 |     typedef const T*                     pointer; | 
 |     typedef const T&                     reference; | 
 |  | 
 |     typedef charT                        char_type; | 
 |     typedef traits                       traits_type; | 
 |     typedef basic_istream<charT, traits> istream_type; | 
 |  | 
 |     constexpr istream_iterator(); | 
 |     istream_iterator(istream_type& s); | 
 |     istream_iterator(const istream_iterator& x); | 
 |     ~istream_iterator(); | 
 |  | 
 |     const T& operator*() const; | 
 |     const T* operator->() const; | 
 |     istream_iterator& operator++(); | 
 |     istream_iterator  operator++(int); | 
 | }; | 
 |  | 
 | template <class T, class charT, class traits, class Distance> | 
 | bool operator==(const istream_iterator<T,charT,traits,Distance>& x, | 
 |                 const istream_iterator<T,charT,traits,Distance>& y); | 
 | template <class T, class charT, class traits, class Distance> | 
 | bool operator!=(const istream_iterator<T,charT,traits,Distance>& x, | 
 |                 const istream_iterator<T,charT,traits,Distance>& y); | 
 |  | 
 | template <class T, class charT = char, class traits = char_traits<charT> > | 
 | class ostream_iterator | 
 |     : public iterator<output_iterator_tag, void, void, void, void> // until C++17 | 
 | { | 
 | public: | 
 |     typedef output_iterator_tag         iterator_category; | 
 |     typedef void                        value_type; | 
 |     typedef void                        difference_type; // until C++20 | 
 |     typedef ptrdiff_t                   difference_type; // since C++20 | 
 |     typedef void                        pointer; | 
 |     typedef void                        reference; | 
 |  | 
 |     typedef charT char_type; | 
 |     typedef traits traits_type; | 
 |     typedef basic_ostream<charT,traits> ostream_type; | 
 |  | 
 |     ostream_iterator(ostream_type& s); | 
 |     ostream_iterator(ostream_type& s, const charT* delimiter); | 
 |     ostream_iterator(const ostream_iterator& x); | 
 |     ~ostream_iterator(); | 
 |     ostream_iterator& operator=(const T& value); | 
 |  | 
 |     ostream_iterator& operator*(); | 
 |     ostream_iterator& operator++(); | 
 |     ostream_iterator& operator++(int); | 
 | }; | 
 |  | 
 | template<class charT, class traits = char_traits<charT> > | 
 | class istreambuf_iterator | 
 |     : public iterator<input_iterator_tag, charT, traits::off_type, unspecified, charT> // until C++17 | 
 | { | 
 | public: | 
 |     typedef input_iterator_tag              iterator_category; | 
 |     typedef charT                           value_type; | 
 |     typedef traits::off_type                difference_type; | 
 |     typedef unspecified                     pointer; | 
 |     typedef charT                           reference; | 
 |  | 
 |     typedef charT                           char_type; | 
 |     typedef traits                          traits_type; | 
 |     typedef traits::int_type                int_type; | 
 |     typedef basic_streambuf<charT, traits>  streambuf_type; | 
 |     typedef basic_istream<charT, traits>    istream_type; | 
 |  | 
 |     istreambuf_iterator() noexcept; | 
 |     istreambuf_iterator(istream_type& s) noexcept; | 
 |     istreambuf_iterator(streambuf_type* s) noexcept; | 
 |     istreambuf_iterator(a-private-type) noexcept; | 
 |  | 
 |     charT                operator*() const; | 
 |     pointer operator->() const; | 
 |     istreambuf_iterator& operator++(); | 
 |     a-private-type       operator++(int); | 
 |  | 
 |     bool equal(const istreambuf_iterator& b) const; | 
 | }; | 
 |  | 
 | template <class charT, class traits> | 
 | bool operator==(const istreambuf_iterator<charT,traits>& a, | 
 |                 const istreambuf_iterator<charT,traits>& b); | 
 | template <class charT, class traits> | 
 | bool operator!=(const istreambuf_iterator<charT,traits>& a, | 
 |                 const istreambuf_iterator<charT,traits>& b); | 
 |  | 
 | template <class charT, class traits = char_traits<charT> > | 
 | class ostreambuf_iterator | 
 |     : public iterator<output_iterator_tag, void, void, void, void> // until C++17 | 
 | { | 
 | public: | 
 |     typedef output_iterator_tag            iterator_category; | 
 |     typedef void                           value_type; | 
 |     typedef void                           difference_type; // until C++20 | 
 |     typedef ptrdiff_t                      difference_type; // since C++20 | 
 |     typedef void                           pointer; | 
 |     typedef void                           reference; | 
 |  | 
 |     typedef charT                          char_type; | 
 |     typedef traits                         traits_type; | 
 |     typedef basic_streambuf<charT, traits> streambuf_type; | 
 |     typedef basic_ostream<charT, traits>   ostream_type; | 
 |  | 
 |     ostreambuf_iterator(ostream_type& s) noexcept; | 
 |     ostreambuf_iterator(streambuf_type* s) noexcept; | 
 |     ostreambuf_iterator& operator=(charT c); | 
 |     ostreambuf_iterator& operator*(); | 
 |     ostreambuf_iterator& operator++(); | 
 |     ostreambuf_iterator& operator++(int); | 
 |     bool failed() const noexcept; | 
 | }; | 
 |  | 
 | template <class C> constexpr auto begin(C& c) -> decltype(c.begin()); | 
 | template <class C> constexpr auto begin(const C& c) -> decltype(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()); | 
 | template <class T, size_t N> constexpr T* begin(T (&array)[N]); | 
 | template <class T, size_t N> constexpr T* end(T (&array)[N]); | 
 |  | 
 | template <class C> auto constexpr cbegin(const C& c) -> decltype(std::begin(c));        // C++14 | 
 | template <class C> auto constexpr cend(const C& c) -> decltype(std::end(c));            // C++14 | 
 | template <class C> auto constexpr rbegin(C& c) -> decltype(c.rbegin());                 // C++14 | 
 | template <class C> auto constexpr rbegin(const C& c) -> decltype(c.rbegin());           // C++14 | 
 | template <class C> auto constexpr rend(C& c) -> decltype(c.rend());                     // C++14 | 
 | template <class C> constexpr auto rend(const C& c) -> decltype(c.rend());               // C++14 | 
 | template <class E> reverse_iterator<const E*> constexpr rbegin(initializer_list<E> il); // C++14 | 
 | template <class E> reverse_iterator<const E*> constexpr rend(initializer_list<E> il);   // C++14 | 
 | template <class T, size_t N> reverse_iterator<T*> constexpr rbegin(T (&array)[N]);      // C++14 | 
 | template <class T, size_t N> reverse_iterator<T*> constexpr rend(T (&array)[N]);        // C++14 | 
 | template <class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c));      // C++14 | 
 | template <class C> constexpr auto crend(const C& c) -> decltype(std::rend(c));          // C++14 | 
 |  | 
 | // 24.8, container access: | 
 | template <class C> constexpr auto size(const C& c) -> decltype(c.size());         // C++17 | 
 | template <class T, size_t N> constexpr size_t size(const T (&array)[N]) noexcept; // C++17 | 
 |  | 
 | template <class C> constexpr auto ssize(const C& c) | 
 |     -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>;                    // C++20 | 
 | template <class T, ptrdiff_t> constexpr ptrdiff_t ssize(const T (&array)[N]) noexcept; // C++20 | 
 |  | 
 | template <class C> constexpr auto empty(const C& c) -> decltype(c.empty());       // C++17 | 
 | template <class T, size_t N> constexpr bool empty(const T (&array)[N]) noexcept;  // C++17 | 
 | template <class E> constexpr bool empty(initializer_list<E> il) noexcept;         // C++17 | 
 | template <class C> constexpr auto data(C& c) -> decltype(c.data());               // C++17 | 
 | template <class C> constexpr auto data(const C& c) -> decltype(c.data());         // C++17 | 
 | template <class T, size_t N> constexpr T* data(T (&array)[N]) noexcept;           // C++17 | 
 | template <class E> constexpr const E* data(initializer_list<E> il) noexcept;      // C++17 | 
 |  | 
 | }  // std | 
 |  | 
 | */ | 
 |  | 
 | #include <__config> | 
 | #include <__debug> | 
 | #include <__functional_base> | 
 | #include <__iterator/access.h> | 
 | #include <__iterator/advance.h> | 
 | #include <__iterator/back_insert_iterator.h> | 
 | #include <__iterator/common_iterator.h> | 
 | #include <__iterator/concepts.h> | 
 | #include <__iterator/counted_iterator.h> | 
 | #include <__iterator/data.h> | 
 | #include <__iterator/default_sentinel.h> | 
 | #include <__iterator/distance.h> | 
 | #include <__iterator/empty.h> | 
 | #include <__iterator/erase_if_container.h> | 
 | #include <__iterator/front_insert_iterator.h> | 
 | #include <__iterator/incrementable_traits.h> | 
 | #include <__iterator/indirectly_comparable.h> | 
 | #include <__iterator/insert_iterator.h> | 
 | #include <__iterator/istream_iterator.h> | 
 | #include <__iterator/istreambuf_iterator.h> | 
 | #include <__iterator/iter_move.h> | 
 | #include <__iterator/iter_swap.h> | 
 | #include <__iterator/iterator.h> | 
 | #include <__iterator/iterator_traits.h> | 
 | #include <__iterator/move_iterator.h> | 
 | #include <__iterator/next.h> | 
 | #include <__iterator/ostream_iterator.h> | 
 | #include <__iterator/ostreambuf_iterator.h> | 
 | #include <__iterator/prev.h> | 
 | #include <__iterator/projected.h> | 
 | #include <__iterator/readable_traits.h> | 
 | #include <__iterator/reverse_access.h> | 
 | #include <__iterator/reverse_iterator.h> | 
 | #include <__iterator/size.h> | 
 | #include <__iterator/unreachable_sentinel.h> | 
 | #include <__iterator/wrap_iter.h> | 
 | #include <__memory/addressof.h> | 
 | #include <__memory/pointer_traits.h> | 
 | #include <__utility/forward.h> | 
 | #include <compare> | 
 | #include <concepts> // Mandated by the Standard. | 
 | #include <cstddef> | 
 | #include <initializer_list> | 
 | #include <type_traits> | 
 | #include <version> | 
 |  | 
 | #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) | 
 | #pragma GCC system_header | 
 | #endif | 
 |  | 
 | #endif // _LIBCPP_ITERATOR |