标准库头文件 <iterator>
来自cppreference.com
此头文件是迭代器库的一部分。
概念 | |
迭代器概念 | |
(C++20) |
指定类型通过应用运算符 * 可读 (概念) |
(C++20) |
指定可向迭代器所引用的对象写入值 (概念) |
(C++20) |
指定 semiregular 类型能以前后自增运算符自增 (概念) |
(C++20) |
指定 weakly_incrementable 类型上的自增操作保持相等性,而且该类型为 equality_comparable (概念) |
(C++20) |
指定该类型对象可以自增且可以解引用 (概念) |
(C++20) |
指定类型为某个 input_or_output_iterator 类型的哨位类型 (概念) |
(C++20) |
指定可对一个迭代器和一个哨位应用 - 运算符,以在常数时间计算其距离 (概念) |
(C++20) |
指定类型为输入迭代器,即可读取其所引用的值,且可前/后自增 (概念) |
(C++20) |
指定类型为给定的值类型的输出迭代器,即可向其写入该类型的值,且可前/后自增 (概念) |
(C++20) |
指定 input_iterator 为向前迭代器,支持相等比较与多趟操作 (概念) |
(C++20) |
指定 forward_iterator 为双向迭代器,支持向后移动 (概念) |
(C++20) |
指定 bidirectional_iterator 为随机访问迭代器,支持常数时间内的前进和下标访问 (概念) |
(C++20) |
指定 random_access_iterator 为连续迭代器,指代内存中连续相接的元素 (概念) |
间接可调用概念 | |
指定可调用类型能以解引用某个 indirectly_readable 类型的结果进行调用 (概念) | |
(C++20) |
指定可调用类型,在以解引用一个 indirectly_readable 类型的结果进行调用时,满足 predicate (概念) |
(C++20) |
指定可调用类型,在以解引用两个 indirectly_readable 类型的结果进行调用时,满足 predicate (概念) |
指定可调用类型,在以解引用两个 indirectly_readable 类型的结果进行调用时,满足 equivalence_relation (概念) | |
(C++20) |
指定可调用类型,在以解引用两个 indirectly_readable 类型的结果进行调用时,满足 strict_weak_order (概念) |
常用算法要求 | |
(C++20) |
指定可从 indirectly_readable 类型移动值给 indirectly_writable 类型 (概念) |
(C++20) |
指定可从 indirectly_readable 类型移动值给 indirectly_writable 类型,且该移动可以通过中间对象进行 (概念) |
(C++20) |
指定可从 indirectly_readable 类型复制值给 indirectly_writable 类型 (概念) |
(C++20) |
指定可从 indirectly_readable 类型复制值给 indirectly_writable 类型,且该复制可以通过中间对象进行 (概念) |
(C++20) |
指定能交换两个 indirectly_readable 类型所引用的值 (概念) |
(C++20) |
指定能比较两个 indirectly_readable 类型所引用的值 (概念) |
(C++20) |
指定在原位重排元素的算法的共同要求 (概念) |
(C++20) |
指定通过复制元素将已排序序列归并到输出序列中的算法的要求 (概念) |
(C++20) |
指定重排序列为有序序列的算法的共用要求 (概念) |
类 | |
算法工具 | |
(C++20) |
计算在解引用某组 indirectly_readable 类型的结果上调用可调用对象的结果 (别名模板) |
(C++20) |
用于对接受投影的算法指定约束的辅助模板 (类模板) |
关联类型 | |
(C++20) |
计算 weakly_incrementable 类型的差类型 (类模板) |
(C++20) |
计算 indirectly_readable 类型的值类型 (类模板) |
(C++20)(C++20)(C++20)(C++20)(C++20) |
计算迭代器的关联类型 (别名模板) |
原语 | |
为迭代器各项性质提供统一接口 (类模板) | |
用于指示迭代器类别的空类类型 (类) | |
(C++17 中弃用) |
用于简化简单的迭代器的必要类型定义的基类 (类模板) |
适配器 | |
逆序遍历的迭代器适配器 (类模板) | |
(C++11) |
解引用结果为右值引用的迭代器适配器 (类模板) |
(C++20) |
用于 std::move_iterator 的哨位适配器 (类模板) |
(C++20) |
适配一个迭代器类型及其哨位为一个公共迭代器类型 (类模板) |
(C++20) |
用于知晓其边界的迭代器的默认哨位 (类) |
(C++20) |
对到范围结尾距离进行跟踪的迭代器适配器 (类模板) |
(C++20) |
始终与任何 weakly_incrementable 类型比较都不相等的哨位 (类) |
用于在容器尾部插入的迭代器适配器 (类模板) | |
用于在容器头部插入的迭代器适配器 (类模板) | |
用于插入容器的迭代器适配器 (类模板) | |
流迭代器 | |
从 std::basic_istream 读取的输入迭代器 (类模板) | |
写入 std::basic_ostream 的输出迭代器 (类模板) | |
从 std::basic_streambuf 读取的输入迭代器 (类模板) | |
写入 std::basic_streambuf 的输出迭代器 (类模板) | |
定制点对象 | |
定义于命名空间
std::ranges | |
(C++20) |
将解引用迭代器的结果转型为其关联的右值引用类型 (定制点对象) |
(C++20) |
交换两个可解引用对象所引用的值 (定制点对象) |
函数 | |
适配器 | |
(C++14) |
创建拥有从实参推出的类型的 std::reverse_iterator (函数模板) |
(C++11) |
创建拥有从实参推出的类型的 std::move_iterator (函数模板) |
创建拥有从实参推出的类型的 std::front_insert_iterator (函数模板) | |
创建拥有从实参推出的类型的 std::back_insert_iterator (函数模板) | |
创建拥有从实参推出的类型的 std::insert_iterator (函数模板) | |
非成员函数 | |
(C++11)(C++11)(C++20 中移除)(C++11)(C++11)(C++11)(C++11)(C++20) |
比较底层迭代器 (函数模板) |
(C++11) |
令迭代器前进 (函数模板) |
(C++11) |
计算两个迭代器适配器间的距离 (函数模板) |
比较底层迭代器 (函数模板) | |
令迭代器前进 (函数模板) | |
计算两个迭代器适配器间的距离 (函数模板) | |
(C++20 中移除) |
比较两个 istream_iterator (函数模板) |
(C++20 中移除) |
比较两个 istreambuf_iterator (函数模板) |
操作 | |
令迭代器前进给定的距离 (函数模板) | |
返回两个迭代器间的距离 (函数模板) | |
(C++11) |
令迭代器自增 (函数模板) |
(C++11) |
令迭代器自减 (函数模板) |
(C++20) |
令迭代器前进给定的距离或到给定的边界 (niebloid) |
(C++20) |
返回迭代器与哨位间的距离,或范围起始与结尾间的距离 (niebloid) |
(C++20) |
自增迭代器给定的距离或到边界 (niebloid) |
(C++20) |
自减迭代器给定的距离或到边界 (niebloid) |
范围访问 | |
(C++11)(C++14) |
返回指向容器或数组起始的迭代器 (函数模板) |
(C++11)(C++14) |
返回指向容器或数组结尾的迭代器 (函数模板) |
(C++14) |
返回指向一个容器或数组的逆向迭代器 (函数模板) |
(C++14) |
返回容器或数组的逆向尾迭代器 (函数模板) |
(C++17)(C++20) |
返回容器或数组的大小 (函数模板) |
(C++17) |
检查容器是否为空 (函数模板) |
(C++17) |
获得指向底层数组的指针 (函数模板) |
概要
#include <concepts> namespace std { template<class T> using __with_reference = T&; // 仅用于阐释 template<class T> concept __Referenceable // 仅用于阐释 = requires { typename __with_reference<T>; }; template<class T> concept __Dereferenceable // 仅用于阐释 = requires(T& t) { { *t } -> __Referenceable; // 不要求保持相等性 }; // 关联类型 // 可自增特征 template<class> struct incrementable_traits; template<class T> using iter_difference_t = /* 见描述 */; // 间接可读特征 template<class> struct indirectly_readable_traits; template<class T> using iter_value_t = /* 见描述 */; // 迭代器特征 template<class I> struct iterator_traits; template<class T> requires is_object_v<T> struct iterator_traits<T*>; template<__Dereferenceable T> using iter_reference_t = decltype(*declval<T&>()); namespace ranges { // 定制点 inline namespace /* 未指明 */ { // ranges::iter_move inline constexpr /* 未指明 */ iter_move = /* 未指明 */; // ranges::iter_swap inline constexpr /* 未指明 */ iter_swap = /* 未指明 */; } } template<__Dereferenceable T> requires requires(T& t) { { ranges::iter_move(t) } -> __Referenceable; } using iter_rvalue_reference_t = decltype(ranges::iter_move(declval<T&>())); // 迭代器概念 // 概念 indirectly_readable template<class In> concept indirectly_readable = /* 见描述 */; template<indirectly_readable T> using iter_common_reference_t = common_reference_t<iter_reference_t<T>, iter_value_t<T>&>; // 概念 indirectly_writable template<class Out, class T> concept indirectly_writable = /* 见描述 */; // 概念 weakly_incrementable template<class I> concept weakly_incrementable = /* 见描述 */; // 概念 incrementable template<class I> concept incrementable = /* 见描述 */; // 概念 input_or_output_iterator template<class I> concept input_or_output_iterator = /* 见描述 */; // 概念 sentinel_for template<class S, class I> concept sentinel_for = /* 见描述 */; // 概念 sized_sentinel_for template<class S, class I> inline constexpr bool disable_sized_sentinel = false; template<class S, class I> concept sized_sentinel_for = /* 见描述 */; // 概念 input_iterator template<class I> concept input_iterator = /* 见描述 */; // 概念 output_iterator template<class I, class T> concept output_iterator = /* 见描述 */; // 概念 forward_iterator template<class I> concept forward_iterator = /* 见描述 */; // 概念 bidirectional_iterator template<class I> concept bidirectional_iterator = /* 见描述 */; // 概念 random_access_iterator template<class I> concept random_access_iterator = /* 见描述 */; // 概念 contiguous_iterator template<class I> concept contiguous_iterator = /* 见描述 */; // 间接可调用要求 // 间接可调用 template<class F, class I> concept indirectly_unary_invocable = /* 见描述 */; template<class F, class I> concept indirectly_regular_unary_invocable = /* 见描述 */; template<class F, class I> concept indirect_unary_predicate = /* 见描述 */; template<class F, class I1, class I2> concept indirect_binary_predicate = /* 见描述 */; template<class F, class I1, class I2 = I1> concept indirect_equivalence_relation = /* 见描述 */; template<class F, class I1, class I2 = I1> concept indirect_strict_weak_order = /* 见描述 */; template<class F, class... Is> requires (indirectly_readable<Is> && ...) && invocable<F, iter_reference_t<Is>...> using indirect_result_t = invoke_result_t<F, iter_reference_t<Is>...>; // projected template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj> struct projected; template<weakly_incrementable I, class Proj> struct incrementable_traits<projected<I, Proj>>; // 常用算法要求 // 概念 indirectly_movable template<class In, class Out> concept indirectly_movable = /* 见描述 */; template<class In, class Out> concept indirectly_movable_storable = /* 见描述 */; // 概念 indirectly_copyable template<class In, class Out> concept indirectly_copyable = /* 见描述 */; template<class In, class Out> concept indirectly_copyable_storable = /* 见描述 */; // 概念 indirectly_swappable template<class I1, class I2 = I1> concept indirectly_swappable = /* 见描述 */; // 概念 indirectly_comparable template<class I1, class I2, class R, class P1 = identity, class P2 = identity> concept indirectly_comparable = /* 见描述 */; // 概念 permutable template<class I> concept permutable = /* 见描述 */; // 概念 mergeable template<class I1, class I2, class Out, class R = ranges::less, class P1 = identity, class P2 = identity> concept mergeable = /* 见描述 */; // 概念 sortable template<class I, class R = ranges::less, class P = identity> concept sortable = /* 见描述 */; // 原语 // 迭代器标签 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 { }; struct contiguous_iterator_tag: public random_access_iterator_tag { }; // 迭代器操作 template<class InputIter, class Distance> constexpr void advance(InputIter& i, Distance n); template<class InputIter> constexpr typename iterator_traits<InputIter>::difference_type distance(InputIter first, InputIter last); template<class InputIter> constexpr InputIter next(InputIter x, typename iterator_traits<InputIter>::difference_type n = 1); template<class BidirectionalIter> constexpr BidirectionalIter prev(BidirectionalIter x, typename iterator_traits<BidirectionalIter>::difference_type n = 1); // 范围迭代器操作 namespace ranges { // ranges::advance template<input_or_output_iterator I> constexpr void advance(I& i, iter_difference_t<I> n); template<input_or_output_iterator I, sentinel_for<I> S> constexpr void advance(I& i, S bound); 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); // ranges::distance template<input_or_output_iterator I, sentinel_for<I> S> constexpr iter_difference_t<I> distance(I first, S last); template<range R> constexpr range_difference_t<R> distance(R&& r); // ranges::next template<input_or_output_iterator I> constexpr I next(I x); template<input_or_output_iterator I> constexpr I next(I x, iter_difference_t<I> n); template<input_or_output_iterator I, sentinel_for<I> S> constexpr I next(I x, S bound); template<input_or_output_iterator I, sentinel_for<I> S> constexpr I next(I x, iter_difference_t<I> n, S bound); // ranges::prev template<bidirectional_iterator I> constexpr I prev(I x); template<bidirectional_iterator I> constexpr I prev(I x, iter_difference_t<I> n); template<bidirectional_iterator I> constexpr I prev(I x, iter_difference_t<I> n, I bound); } // 预定义迭代器与哨位 // 逆向迭代器 template<class Iter> class reverse_iterator; template<class Iter1, class Iter2> constexpr bool operator==( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator!=( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator<( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator>( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator<=( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator>=( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, three_way_comparable_with<Iter1> Iter2> constexpr compare_three_way_result_t<Iter1, Iter2> operator<=>(const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr auto operator-( const reverse_iterator<Iter1>& x, const reverse_iterator<Iter2>& y) -> decltype(y.base() - x.base()); template<class Iter> constexpr reverse_iterator<Iter> operator+( typename reverse_iterator<Iter>::difference_type n, const reverse_iterator<Iter>& x); template<class Iter> constexpr reverse_iterator<Iter> make_reverse_iterator(Iter i); template<class Iter1, class Iter2> requires (!sized_sentinel_for<Iter1, Iter2>) inline constexpr bool disable_sized_sentinel<reverse_iterator<Iter1>, reverse_iterator<Iter2>> = true; // 插入迭代器 template<class Container> class back_insert_iterator; template<class Container> constexpr back_insert_iterator<Container> back_inserter(Container& x); template<class Container> class front_insert_iterator; template<class Container> constexpr front_insert_iterator<Container> front_inserter(Container& x); template<class Container> class insert_iterator; template<class Container> constexpr insert_iterator<Container> inserter(Container& x, ranges::iterator_t<Container> i); // 移动迭代器与哨位 template<class Iter> class move_iterator; template<class Iter1, class Iter2> constexpr bool operator==( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator<( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator>( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator<=( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr bool operator>=( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, three_way_comparable_with<Iter1> Iter2> constexpr compare_three_way_result_t<Iter1, Iter2> operator<=>(const move_iterator<Iter1>& x, const move_iterator<Iter2>& y); template<class Iter1, class Iter2> constexpr auto operator-( const move_iterator<Iter1>& x, const move_iterator<Iter2>& y) -> decltype(x.base() - y.base()); template<class Iter> constexpr move_iterator<Iter> operator+( typename move_iterator<Iter>::difference_type n, const move_iterator<Iter>& x); template<class Iter> constexpr move_iterator<Iter> make_move_iterator(Iter i); template<semiregular S> class move_sentinel; // 公共迭代器 template<input_or_output_iterator I, sentinel_for<I> S> requires (!same_as<I, S>) class common_iterator; template<class I, class S> struct incrementable_traits<common_iterator<I, S>>; template<input_iterator I, class S> struct iterator_traits<common_iterator<I, S>>; // 默认哨位 struct default_sentinel_t; inline constexpr default_sentinel_t default_sentinel{}; // 计数迭代器 template<input_or_output_iterator I> class counted_iterator; template<class I> struct incrementable_traits<counted_iterator<I>>; template<input_iterator I> struct iterator_traits<counted_iterator<I>>; // 不可达哨位 struct unreachable_sentinel_t; inline constexpr unreachable_sentinel_t unreachable_sentinel{}; // 流迭代器 template<class T, class charT = char, class traits = char_traits<charT>, class Distance = ptrdiff_t> class istream_iterator; 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; template<class charT, class traits = char_traits<charT>> class istreambuf_iterator; 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; // 范围访问 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 (&a)[N]) noexcept; template<class T, size_t N> constexpr T* end(T (&a)[N]) noexcept; template<class C> constexpr auto cbegin(const C& c) noexcept(noexcept(std::begin(c))) -> decltype(std::begin(c)); template<class C> constexpr auto cend(const C& c) noexcept(noexcept(std::end(c))) -> decltype(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()); template<class C> constexpr auto rend(C& c) -> decltype(c.rend()); template<class C> constexpr auto rend(const C& c) -> decltype(c.rend()); template<class T, size_t N> constexpr reverse_iterator<T*> rbegin(T (&a)[N]); template<class T, size_t N> constexpr reverse_iterator<T*> rend(T (&a)[N]); template<class E> constexpr reverse_iterator<const E*> rbegin(initializer_list<E> il); template<class E> constexpr reverse_iterator<const E*> rend(initializer_list<E> il); template<class C> constexpr auto crbegin(const C& c) -> decltype(std::rbegin(c)); template<class C> constexpr auto crend(const C& c) -> decltype(std::rend(c)); template<class C> constexpr auto size(const C& c) -> decltype(c.size()); template<class T, size_t N> constexpr size_t size(const T (&a)[N]) noexcept; template<class C> constexpr auto ssize(const C& c) -> common_type_t<ptrdiff_t, make_signed_t<decltype(c.size())>>; template<class T, ptrdiff_t N> constexpr ptrdiff_t ssize(const T (&a)[N]) noexcept; template<class C> [[nodiscard]] constexpr auto empty(const C& c) -> decltype(c.empty()); template<class T, size_t N> [[nodiscard]] constexpr bool empty(const T (&a)[N]) noexcept; template<class E> [[nodiscard]] constexpr bool empty(initializer_list<E> il) noexcept; template<class C> constexpr auto data(C& c) -> decltype(c.data()); template<class C> constexpr auto data(const C& c) -> decltype(c.data()); template<class T, size_t N> constexpr T* data(T (&a)[N]) noexcept; template<class E> constexpr const E* data(initializer_list<E> il) noexcept; }
概念 indirectly_readable
namespace std { template<class In> concept __IndirectlyReadableImpl = // 仅用于阐释 requires(const In in) { typename iter_value_t<In>; typename iter_reference_t<In>; typename iter_rvalue_reference_t<In>; { *in } -> same_as<iter_reference_t<In>> { iter_move(in) } -> same_as<iter_rvalue_reference_t<In>> } && common_reference_with<iter_reference_t<In>&&, iter_value_t<In>&> && common_reference_with<iter_reference_t<In>&&, iter_rvalue_reference_t<In>&&> && common_reference_with<iter_rvalue_reference_t<In>&&, const iter_value_t<In>&>; template<class In> concept indirectly_readable = __IndirectlyReadableImpl<remove_cvref_t<In>> }
概念 indirectly_writable
namespace std { template<class Out, class T> concept indirectly_writable = requires(Out&& o, T&& t) { *o = std::forward<T>(t); // 不要求保持相等性 *std::forward<Out>(o) = std::forward<T>(t); // 不要求保持相等性 const_cast<const iter_reference_t<Out>&&>(*o) = std::forward<T>(t); // 不要求保持相等性 const_cast<const iter_reference_t<Out>&&>(*std::forward<Out>(o)) = std::forward<T>(t); // 不要求保持相等性 }; }
概念 weakly_incrementable
namespace std { template<class T> inline constexpr bool __is_integer_like = /* 见描述 */; // 仅用于阐释 template<class T> inline constexpr bool __is_signed_integer_like = // 仅用于阐释 /* 见描述 */; template<class I> concept weakly_incrementable = default_initializable<I> && movable<I> && requires(I i) { typename iter_difference_t<I>; requires __is_signed_integer_like<iter_difference_t<I>>; { ++i } -> same_as<I&>; // 不要求保持相等性 i++; // 不要求保持相等性 }; }
概念 incrementable
namespace std { template<class I> concept incrementable = regular<I> && weakly_incrementable<I> && requires(I i) { { i++ } -> same_as<I>; }; }
概念 input_or_output_iterator
namespace std { template<class I> concept input_or_output_iterator = requires(I i) { { *i } -> can-reference; } && weakly_incrementable<I>; }
概念 sentinel_for
namespace std { template<class S, class I> concept sentinel_for = semiregular<S> && input_or_output_iterator<I> && __WeaklyEqualityComparableWith<S, I>; }
概念 sized_sentinel_for
namespace std { template<class S, class I> concept sized_sentinel_for = sentinel_for<S, I> && !disable_sized_sentinel<remove_cv_t<S>, remove_cv_t<I>> && requires(const I& i, const S& s) { { s - i } -> same_as<iter_difference_t<I>>; { i - s } -> same_as<iter_difference_t<I>>; }; }
概念 input_iterator
namespace std { template<class I> concept input_iterator = input_or_output_iterator<I> && indirectly_readable<I> && requires { typename /*ITER_CONCEPT*/(I); } && derived_from</*ITER_CONCEPT*/(I), input_iterator_tag>; }
概念 output_iterator
namespace std { template<class I, class T> concept output_iterator = input_or_output_iterator<I> && indirectly_writable<I, T> && requires(I i, T&& t) { *i++ = std::forward<T>(t); // 不要求保持相等性 }; }
概念 forward_iterator
namespace std { template<class I> concept forward_iterator = input_iterator<I> && derived_from</*ITER_CONCEPT*/(I), forward_iterator_tag> && incrementable<I> && sentinel_for<I, I>; }
概念 bidirectional_iterator
namespace std { template<class I> concept bidirectional_iterator = forward_iterator<I> && derived_from</*ITER_CONCEPT*/(I), bidirectional_iterator_tag> && requires(I i) { { --i } -> same_as<I&>; { i-- } -> same_as<I>; }; }
概念 random_access_iterator
namespace std { template<class I> concept random_access_iterator = bidirectional_iterator<I> && derived_from</*ITER_CONCEPT*/(I), random_access_iterator_tag> && totally_ordered<I> && sized_sentinel_for<I, I> && requires(I i, const I j, const iter_difference_t<I> n) { { i += n } -> same_as<I&>; { j + n } -> same_as<I>; { n + j } -> same_as<I>; { i -= n } -> same_as<I&>; { j - n } -> same_as<I>; { j[n] } -> same_as<iter_reference_t<I>>; }; }
概念 contiguous_iterator
namespace std { template<class I> concept contiguous_iterator = random_access_iterator<I> && derived_from</*ITER_CONCEPT*/(I), contiguous_iterator_tag> && is_lvalue_reference_v<iter_reference_t<I>> && same_as<iter_value_t<I>, remove_cvref_t<iter_reference_t<I>>> && requires(const I& i) { { to_address(i) } -> same_as<add_pointer_t<iter_reference_t<I>>>; }; }
概念 indirectly_unary_invocable
namespace std { template<class F, class I> concept indirectly_unary_invocable = indirectly_readable<I> && copy_constructible<F> && invocable<F&, iter_value_t<I>&> && invocable<F&, iter_reference_t<I>> && invocable<F&, iter_common_reference_t<I>> && common_reference_with< invoke_result_t<F&, iter_value_t<I>&>, invoke_result_t<F&, iter_reference_t<I>>>; }
概念 indirectly_regular_unary_invocable
namespace std { template<class F, class I> concept indirectly_regular_unary_invocable = indirectly_readable<I> && copy_constructible<F> && regular_invocable<F&, iter_value_t<I>&> && regular_invocable<F&, iter_reference_t<I>> && regular_invocable<F&, iter_common_reference_t<I>> && common_reference_with< invoke_result_t<F&, iter_value_t<I>&>, invoke_result_t<F&, iter_reference_t<I>>>; }
概念 indirect_unary_predicate
namespace std { template<class F, class I> concept indirect_unary_predicate = indirectly_readable<I> && copy_constructible<F> && predicate<F&, iter_value_t<I>&> && predicate<F&, iter_reference_t<I>> && predicate<F&, iter_common_reference_t<I>>; }
概念 indirect_binary_predicate
namespace std { template<class F, class I1, class I2 = I1> concept indirect_binary_predicate = indirectly_readable<I1> && indirectly_readable<I2> && copy_constructible<F> && predicate<F&, iter_value_t<I1>&, iter_value_t<I2>&> && predicate<F&, iter_value_t<I1>&, iter_reference_t<I2>> && predicate<F&, iter_reference_t<I1>, iter_value_t<I2>&> && predicate<F&, iter_reference_t<I1>, iter_reference_t<I2>> && predicate<F&, iter_common_reference_t<I1>, iter_common_reference_t<I2>>; }
概念 indirect_equivalence_relation
namespace std { template<class F, class I1, class I2 = I1> concept indirect_equivalence_relation = indirectly_readable<I1> && indirectly_readable<I2> && copy_constructible<F> && equivalence_relation<F&, iter_value_t<I1>&, iter_value_t<I2>&> && equivalence_relation<F&, iter_value_t<I1>&, iter_reference_t<I2>> && equivalence_relation<F&, iter_reference_t<I1>, iter_value_t<I2>&> && equivalence_relation<F&, iter_reference_t<I1>, iter_reference_t<I2>> && equivalence_relation<F&, iter_common_reference_t<I1>, iter_common_reference_t<I2>>; }
概念 indirect_strict_weak_order
namespace std { template<class F, class I1, class I2 = I1> concept indirect_strict_weak_order = indirectly_readable<I1> && indirectly_readable<I2> && copy_constructible<F> && strict_weak_order<F&, iter_value_t<I1>&, iter_value_t<I2>&> && strict_weak_order<F&, iter_value_t<I1>&, iter_reference_t<I2>> && strict_weak_order<F&, iter_reference_t<I1>, iter_value_t<I2>&> && strict_weak_order<F&, iter_reference_t<I1>, iter_reference_t<I2>> && strict_weak_order<F&, iter_common_reference_t<I1>, iter_common_reference_t<I2>>; }
概念 indirectly_movable
namespace std { template<class In, class Out> concept indirectly_movable = indirectly_readable<In> && indirectly_writable<Out, iter_rvalue_reference_t<In>>; }
概念 indirectly_movable_storable
namespace std { template<class In, class Out> concept indirectly_movable_storable = indirectly_movable<In, Out> && indirectly_writable<Out, iter_value_t<In>> && movable<iter_value_t<In>> && constructible_from<iter_value_t<In>, iter_rvalue_reference_t<In>> && assignable_from<iter_value_t<In>&, iter_rvalue_reference_t<In>>; }
概念 indirectly_copyable
namespace std { template<class In, class Out> concept indirectly_copyable = indirectly_readable<In> && indirectly_writable<Out, iter_reference_t<In>>; }
概念 indirectly_copyable_storable
namespace std { template<class In, class Out> concept indirectly_copyable_storable = indirectly_copyable<In, Out> && indirectly_writable<Out, iter_value_t<In>&> && indirectly_writable<Out, const iter_value_t<In>&> && indirectly_writable<Out, iter_value_t<In>&&> && indirectly_writable<Out, const iter_value_t<In>&&> && copyable<iter_value_t<In>> && constructible_from<iter_value_t<In>, iter_reference_t<In>> && assignable_from<iter_value_t<In>&, iter_reference_t<In>>; }
概念 indirectly_swappable
namespace std { template<class I1, class I2 = I1> concept indirectly_swappable = indirectly_readable<I1> && indirectly_readable<I2> && requires(const I1 i1, const I2 i2) { ranges::iter_swap(i1, i1); ranges::iter_swap(i2, i2); ranges::iter_swap(i1, i2); ranges::iter_swap(i2, i1); }; }
概念 indirectly_comparable
namespace std { template<class I1, class I2, class R, class P1 = identity, class P2 = identity> concept indirectly_comparable = indirect_relation<R, projected<I1, P1>, projected<I2, P2>>; }
概念 permutable
namespace std { template<class I> concept permutable = forward_iterator<I> && indirectly_movable_storable<I, I> && indirectly_swappable<I, I>; }
概念 mergeable
namespace std { template<class I1, class I2, class Out, class R = ranges::less, class P1 = identity, class P2 = identity> concept mergeable = input_iterator<I1> && input_iterator<I2> && weakly_incrementable<Out> && indirectly_copyable<I1, Out> && indirectly_copyable<I2, Out> && indirect_strict_weak_order<R, projected<I1, P1>, projected<I2, P2>>; }
概念 sortable
namespace std { template<class I, class R = ranges::less, class P = identity> concept sortable = permutable<I> && indirect_strict_weak_order<R, projected<I, P>>; }
类模板 std::incrementable_traits
namespace std { template<class> struct incrementable_traits { }; template<class T> requires is_object_v<T> struct incrementable_traits<T*> { using difference_type = ptrdiff_t; }; template<class I> struct incrementable_traits<const I> : incrementable_traits<I> { }; template<class T> requires requires { typename T::difference_type; } struct incrementable_traits<T> { using difference_type = typename T::difference_type; }; template<class T> requires (!requires { typename T::difference_type; } && requires(const T& a, const T& b) { { a - b } -> integral; }) struct incrementable_traits<T> { using difference_type = make_signed_t<decltype(declval<T>() - declval<T>())>; }; template<class T> using iter_difference_t = /* 见描述 */; }
类模板 std::indirectly_readable_traits
namespace std { template<class> struct __cond_value_type { }; // 仅用于阐释 template<class T> requires is_object_v<T> struct __cond_value_type { using value_type = remove_cv_t<T>; }; template<class> struct indirectly_readable_traits { }; template<class T> struct indirectly_readable_traits<T*> : __cond_value_type<T> { }; template<class I> requires is_array_v<I> struct indirectly_readable_traits<I> { using value_type = remove_cv_t<remove_extent_t<I>>; }; template<class I> struct indirectly_readable_traits<const I> : indirectly_readable_traits<I> { }; template<class T> requires requires { typename T::value_type; } struct indirectly_readable_traits<T> : __cond_value_type<typename T::value_type> { }; template<class T> requires requires { typename T::element_type; } struct indirectly_readable_traits<T> : __cond_value_type<typename T::element_type> { }; }
类模板 std::projected
namespace std { template<indirectly_readable I, indirectly_regular_unary_invocable<I> Proj> struct projected { using value_type = remove_cvref_t<indirect_result_t<Proj&, I>>; indirect_result_t<Proj&, I> operator*() const; // 不定义 }; template<weakly_incrementable I, class Proj> struct incrementable_traits<projected<I, Proj>> { using difference_type = iter_difference_t<I>; }; }
类模板 std::iterator_traits
namespace std { template<class I> struct iterator_traits { using iterator_category = /* 见描述 */; using value_type = /* 见描述 */; using difference_type = /* 见描述 */; using pointer = /* 见描述 */; using reference = /* 见描述 */; }; template<class T> requires is_object_v<T> struct iterator_traits<T*> { using iterator_concept = contiguous_iterator_tag; using iterator_category = random_access_iterator_tag; using value_type = remove_cv_t<T>; using difference_type = ptrdiff_t; using pointer = T*; using reference = T&; }; }
迭代器标签
namespace std { 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 { }; struct contiguous_iterator_tag: public random_access_iterator_tag { }; }
类模板 std::reverse_iterator
namespace std { template<class Iter> class reverse_iterator { public: using iterator_type = Iter; using iterator_concept = /* 见描述 */; using iterator_category = /* 见描述 */; using value_type = iter_value_t<Iter>; using difference_type = iter_difference_t<Iter>; using pointer = typename iterator_traits<Iter>::pointer; using reference = iter_reference_t<Iter>; constexpr reverse_iterator(); constexpr explicit reverse_iterator(Iter 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 Iter base() const; constexpr reference operator*() const; constexpr pointer operator->() const requires /* 见描述 */; 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 /* 未指明 */ operator[](difference_type n) const; friend constexpr iter_rvalue_reference_t<Iter> iter_move(const reverse_iterator& i) noexcept(/* 见描述 */); template<indirectly_swappable<Iter> Iter2> friend constexpr void iter_swap(const reverse_iterator& x, const reverse_iterator<Iter2>& y) noexcept(/* 见描述 */); protected: Iter current; }; }
类模板 std::back_insert_iterator
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); }; }
类模板 std::front_insert_iterator
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(Container& x) 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); }; }
类模板 std::insert_iterator
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); }; }
类模板 std::move_iterator
namespace std { template<class Iter> class move_iterator { public: using iterator_type = Iter; using iterator_concept = input_iterator_tag; using iterator_category = /* 见描述 */; using value_type = iter_value_t<Iter>; using difference_type = iter_difference_t<Iter>; using pointer = Iter; using reference = iter_rvalue_reference_t<Iter>; constexpr move_iterator(); constexpr explicit move_iterator(Iter 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 pointer 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<Iter> S> friend constexpr bool operator==(const move_iterator& x, const move_sentinel<S>& y); template<sized_sentinel_for<Iter> S> friend constexpr iter_difference_t<Iter> operator-(const move_sentinel<S>& x, const move_iterator& y); template<sized_sentinel_for<Iter> S> friend constexpr iter_difference_t<Iter> operator-(const move_iterator& x, const move_sentinel<S>& y); friend constexpr iter_rvalue_reference_t<Iter> iter_move(const move_iterator& i) noexcept(noexcept(ranges::iter_move(i.current))); template<indirectly_swappable<Iter> Iter2> friend constexpr void iter_swap(const move_iterator& x, const move_iterator<Iter2>& y) noexcept(noexcept(ranges::iter_swap(x.current, y.current))); private: Iter current; // 仅用于阐释 }; }
类模板 std::move_sentinel
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; // 仅用于阐释 }; }
类模板 std::common_iterator
namespace std { template<input_or_output_iterator I, sentinel_for<I> S> requires (!same_as<I, S>) 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 /* 见描述 */; 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_; // 仅用于阐释 }; 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 = /* 见描述 */; using iterator_category = /* 见描述 */; using value_type = iter_value_t<I>; using difference_type = iter_difference_t<I>; using pointer = /* 见描述 */; using reference = iter_reference_t<I>; }; }
类 std::default_sentinel_t
namespace std { struct default_sentinel_t { }; }
类模板 std::counted_iterator
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(); // 仅用于阐释 iter_difference_t<I> length = 0; // 仅用于阐释 }; 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; }; }
类 std::unreachable_sentinel_t
namespace std { struct unreachable_sentinel_t { template<weakly_incrementable I> friend constexpr bool operator==(unreachable_sentinel_t, const I&) noexcept { return false; } }; }
类模板 std::istream_iterator
namespace std { template<class T, class CharT = char, class Traits = char_traits<CharT>, class Distance = ptrdiff_t> class istream_iterator { public: using iterator_category = input_iterator_tag; using value_type = T; using difference_type = Distance; using pointer = const T*; using reference = const T&; using char_type = CharT; using traits_type = Traits; using istream_type = basic_istream<CharT, Traits>; constexpr istream_iterator(); constexpr istream_iterator(default_sentinel_t); istream_iterator(istream_type& s); istream_iterator(const istream_iterator& x) = default; ~istream_iterator() = default; istream_iterator& operator=(const istream_iterator&) = default; const T& operator*() const; const T* operator->() const; istream_iterator& operator++(); istream_iterator operator++(int); friend bool operator==(const istream_iterator& i, default_sentinel_t); private: basic_istream<CharT, Traits>* in_stream; // 仅用于阐释 T value; // 仅用于阐释 }; }
类模板 std::ostream_iterator
namespace std { template<class T, class CharT = char, classTraits = char_traits<CharT>> class ostream_iterator { public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using char_type = CharT; using traits_type = Traits; using ostream_type = basic_ostream<CharT, Traits>; constexpr ostreambuf_iterator() noexcept = default; 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 ostream_iterator&) = default; ostream_iterator& operator=(const T& value); ostream_iterator& operator*(); ostream_iterator& operator++(); ostream_iterator& operator++(int); private: basic_ostream<CharT, Traits>* out_stream = nullptr; // 仅用于阐释 const CharT* delim = nullptr; // 仅用于阐释 }; }
类模板 std::istreambuf_iterator
namespace std { template<class CharT, class Traits = char_traits<CharT>> class istreambuf_iterator { public: using iterator_category = input_iterator_tag; using value_type = CharT; using difference_type = typename Traits::off_type; using pointer = /* 未指明 */; using reference = CharT; using char_type = CharT; using traits_type = Traits; using int_type = typename Traits::int_type; using streambuf_type = basic_streambuf<CharT, Traits>; using istream_type = basic_istream<CharT, Traits>; class proxy; // 仅用于阐释 constexpr istreambuf_iterator() noexcept; constexpr istreambuf_iterator(default_sentinel_t) noexcept; istreambuf_iterator(const istreambuf_iterator&) noexcept = default; ~istreambuf_iterator() = default; istreambuf_iterator(istream_type& s) noexcept; istreambuf_iterator(streambuf_type* s) noexcept; istreambuf_iterator(const proxy& p) noexcept; istreambuf_iterator& operator=(const istreambuf_iterator&) noexcept = default; CharT operator*() const; istreambuf_iterator& operator++(); proxy operator++(int); bool equal(const istreambuf_iterator& b) const; friend bool operator==(const istreambuf_iterator& i, default_sentinel_t s); private: streambuf_type* sbuf_; // 仅用于阐释 }; template<class CharT, class Traits> class istreambuf_iterator<CharT, Traits>::proxy { // 仅用于阐释 CharT keep_; basic_streambuf<CharT, Traits>* sbuf_; proxy(CharT c, basic_streambuf<CharT, Traits>* sbuf) : keep_(c), sbuf_(sbuf) { } public: CharT operator*() { return keep_; } }; }
类模板 std::ostreambuf_iterator
namespace std { template<class CharT, class Traits = char_traits<CharT>> class ostreambuf_iterator { public: using iterator_category = output_iterator_tag; using value_type = void; using difference_type = ptrdiff_t; using pointer = void; using reference = void; using char_type = CharT; using traits_type = Traits; using streambuf_type = basic_streambuf<CharT, Traits>; using ostream_type = basic_ostream<CharT, Traits>; constexpr ostreambuf_iterator() noexcept = default; 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; private: streambuf_type* sbuf_ = nullptr; // 仅用于阐释 }; }
类模板 std::iterator
namespace std { template<class Category, class T, class Distance = ptrdiff_t, class Pointer = T*, class Reference = T&> struct iterator { typedef Category iterator_category; typedef T value_type; typedef Distance difference_type; typedef Pointer pointer; typedef Reference reference; }; }