實驗性庫標頭檔案 <experimental/ranges/iterator>

 

C++

編譯器支援

自由（freestanding）與宿主（hosted）

語言

標準庫

標準庫標頭檔案

具名要求

特性測試宏 (C++20)

語言支援庫

概念庫 (C++20)

診斷庫

記憶體管理庫

超程式設計庫 (C++11)

通用工具庫

容器庫

迭代器庫

範圍庫 (C++20)

演算法庫

字串庫

文字處理庫

數值庫

日期和時間庫

輸入/輸出庫

檔案系統庫 (C++17)

併發支援庫 (C++11)

執行控制庫 (C++26)

技術規範

符號索引

外部庫

 

標準庫標頭檔案

語言支援 <cfloat> <climits> <compare> (C++20) <contracts> (C++26) <coroutine> (C++20) <csetjmp> <csignal> <cstdarg> <cstddef> <cstdint> (C++11) <cstdlib> <exception> <initializer_list> (C++11)    <limits> <new> <source_location> (C++20) <stdfloat> (C++23) <typeinfo> <version> (C++20) 概念 <concepts> (C++20) 診斷 <cassert> <cerrno> <debugging> (C++26) <stacktrace> (C++23) <stdexcept> <system_error> (C++11) 記憶體管理 <memory> <memory_resource> (C++17) <scoped_allocator> (C++11) 超程式設計 <type_traits> (C++11) <ratio> (C++11)

通用工具 <any> (C++17) <bitset> <bit> (C++20) <charconv> (C++17) <expected> (C++23) <format> (C++20) <functional> <optional> (C++17) <tuple> (C++11) <typeindex> (C++11) <utility> <variant> (C++17) 容器 <array> (C++11) <deque> <flat_map> (C++23) <flat_set> (C++23) <forward_list> (C++11) <hive> (C++26) <inplace_vector> (C++26)    <list> <map> <mdspan> (C++23) <queue> <set> <span> (C++20) <stack> <unordered_map> (C++11) <unordered_set> (C++11) <vector> 迭代器 <iterator> Ranges <generator> (C++23) <ranges> (C++20)

演算法 <algorithm> <numeric> 字串 <cctype> <cstring> <cuchar> (C++11) <cwchar> <cwctype> <string_view> (C++17) <string> 文字處理 <clocale> <codecvt> (C++11/17/26*) <locale> <regex> (C++11) <text_encoding> (C++26)    數值 <cfenv> (C++11) <cmath> <complex> <linalg> (C++26) <numbers> (C++20) <random> (C++11) <simd> (C++26) <valarray> 時間 <chrono> (C++11) <ctime> C 相容性 <ccomplex> (C++11/17/20*) <ciso646> (直到 C++20) <cstdalign> (C++11/17/20*) <cstdbool> (C++11/17/20*) <ctgmath> (C++11/17/20*)

輸入/輸出 <cinttypes> (C++11) <cstdio> <filesystem> (C++17) <fstream> <iomanip> <iosfwd> <iostream> <ios> <istream> <ostream> <print> (C++23) <spanstream> (C++23) <sstream> <streambuf> <strstream> (C++98/26*) <syncstream> (C++20) 併發支援 <atomic> (C++11) <barrier> (C++20) <condition_variable> (C++11) <future> (C++11) <hazard_pointer> (C++26) <latch> (C++20) <mutex> (C++11) <rcu> (C++26) <semaphore> (C++20) <shared_mutex> (C++14) <stdatomic.h> (C++23) <stop_token> (C++20) <thread> (C++11) 執行支援 <execution> (C++17)

 

實驗性庫標頭檔案

執行 P2300
<experimental/execution>
檔案系統 TS
<experimental/filesystem>
並行性 TS (v1, v2)
experimental/algorithm experimental/execution_policy experimental/exception_list	experimental/numeric <experimental/simd> experimental/task_block
庫基礎 TS (v1, v2, v3)
experimental/algorithm <experimental/any> experimental/array experimental/chrono experimental/deque experimental/forward_list <experimental/functional> experimental/future experimental/iterator experimental/list experimental/map experimental/memory <experimental/memory_resource> experimental/numeric <experimental/optional> experimental/propagate_const	experimental/random experimental/ratio experimental/regex experimental/scope experimental/set experimental/source_location experimental/string <experimental/string_view> experimental/system_error experimental/tuple experimental/type_traits experimental/unordered_map experimental/unordered_set experimental/utility experimental/vector
併發 TS
experimental/atomic experimental/barrier	experimental/future experimental/latch
範圍 TS
<experimental/ranges/algorithm> <experimental/ranges/concepts> <experimental/ranges/functional>         <experimental/ranges/iterator>	<experimental/ranges/random> <experimental/ranges/tuple> <experimental/ranges/type_traits> <experimental/ranges/utility>
協程 TS
experimental/coroutine
網路 TS
experimental/buffer experimental/executor experimental/internet experimental/io_context	<experimental/net> experimental/netfwd experimental/socket experimental/timer
反射 TS
<experimental/reflect>

 

此標頭檔案是 ranges 庫的一部分。

迭代器相關概念

定義於名稱空間 std::experimental::ranges

迭代器概念

Readable	指定型別透過應用運算子 * 可讀 (概念)
Writable	指定值可以寫入迭代器引用的物件 (概念)
WeaklyIncrementable	指定 Semiregular 型別可以透過前置和後置增量運算子遞增 (概念)
Incrementable	指定 WeaklyIncrementable 型別的增量操作是等價保持的，並且該型別是 EqualityComparable 的 (概念)
迭代器 (Iterator)	指定型別物件可以被增量和解引用 (概念)
哨兵 (Sentinel)	指定某種型別的物件是 Iterator 型別的哨兵 (概念)
SizedSentinel	指定 - 運算子可應用於迭代器和哨兵以在常數時間內計算它們的差值 (概念)
InputIterator	指定型別是一個輸入迭代器，即其引用的值可讀，並且可以進行前置和後置增量 (概念)
OutputIterator	指定型別是給定值型別的輸出迭代器，即該型別的值可以寫入其中，並且可以進行前置和後置增量 (概念)
ForwardIterator	指定 InputIterator 是一個前向迭代器，支援相等比較和多遍遍歷 (概念)
BidirectionalIterator	指定 ForwardIterator 是一個雙向迭代器，支援向後移動 (概念)
RandomAccessIterator	指定 BidirectionalIterator 是一個隨機訪問迭代器，支援常數時間內的前進和下標訪問 (概念)

間接可呼叫概念

IndirectUnaryInvocableIndirectRegularUnaryInvocable	指定一個可呼叫型別可以用解引用 Readable 型別的結果來呼叫 (概念)
IndirectUnaryPredicate	指定一個可呼叫物件，當用解引用 Readable 型別的結果來呼叫時，滿足 Predicate (概念)
IndirectRelation	指定一個可呼叫物件，當用解引用某些 Readable 型別的結果來呼叫時，滿足 Relation (概念)
IndirectStrictWeakOrder	指定一個可呼叫物件，當用解引用某些 Readable 型別的結果來呼叫時，滿足 StrictWeakOrder (概念)

通用演算法要求

IndirectlyMovable	指定值可以從 Readable 型別移動到 Writable 型別 (概念)
IndirectlyMovableStorable	指定值可以從 Readable 型別移動到 Writable 型別，並且可以透過中間物件執行移動 (概念)
IndirectlyCopyable	指定值可以從 Readable 型別複製到 Writable 型別 (概念)
IndirectlyCopyableStorable	指定值可以從 Readable 型別複製到 Writable 型別，並且可以透過中間物件執行復制 (概念)
IndirectlySwappable	指定兩個 Readable 型別引用的值可以互換 (概念)
IndirectlyComparable	指定兩個 Readable 型別引用的值可以比較 (概念)
Permutable	指定就地重新排序元素的演算法的共同要求 (概念)
Mergeable	指定透過複製元素將已排序序列合併到輸出序列中的演算法的要求 (概念)
Sortable	指定將序列排列成有序序列的演算法的共同要求 (概念)

概念實用工具

indirect_result_of	計算在解引用某些 Readable 型別集的結果上呼叫可呼叫物件的結果 (類模板)
projected	用於指定接受投影的演算法約束的輔助模板 (類模板)

迭代器原語

迭代器實用工具

定義於名稱空間 std::experimental::ranges
iter_move	將解引用物件的結果轉換為其關聯的右值引用型別 (定製點物件)
iter_swap	交換兩個可解引用物件引用的值 (定製點物件)

迭代器特性

定義於名稱空間 std::experimental::ranges
difference_type	獲取 WeaklyIncrementable 型別的差值型別 (類模板)
value_type	獲取 Readable 型別的值型別 (類模板)
iterator_category	獲取輸入迭代器型別的迭代器類別 (類模板)
iterator_traits	收集迭代器相關型別的相容性特徵類 (別名模板)
reference_trvalue_reference_titer_common_reference_t	獲取可解引用物件的關聯引用型別 (別名模板)

迭代器類別標籤

定義於名稱空間 std::experimental::ranges
input_iterator_tagoutput_iterator_tagforward_iterator_tagbidirectional_iterator_tagrandom_access_iterator_tag	用於指示迭代器類別的空類型別 (類)

std::iterator_traits 特化

定義於名稱空間 std
std::iterator_traits<InputIterator>std::iterator_traits<OutputIterator>	為 ranges TS 迭代器特化 std::iterator_traits (類模板特化)

迭代器操作

定義於名稱空間 std::experimental::ranges
advance	按給定距離前進迭代器 (函式模板)
distance	返回迭代器與哨兵之間，或範圍的起始與結束之間的距離 (函式模板)
next	遞增迭代器 (函式模板)
prev	遞減迭代器 (函式模板)

迭代器介面卡

定義於名稱空間 std::experimental::ranges
reverse_iterator	用於反向遍歷的迭代器介面卡 (類模板)
back_insert_iterator	用於在容器末尾插入的迭代器介面卡 (類模板)
front_insert_iterator	用於在容器前端插入的迭代器介面卡 (類模板)
insert_iterator	用於在容器中插入的迭代器介面卡 (類模板)
move_iterator	解引用為右值引用的迭代器介面卡 (類模板)
move_sentinel	用於 move_iterator 的哨兵介面卡 (類模板)
common_iterator	將迭代器-哨兵對適配為通用迭代器型別，用於傳統演算法 (類模板)
counted_iterator	迭代器介面卡，跟蹤其與起始位置的距離 (類模板)
default_sentinel	用於已知其範圍邊界的迭代器型別的空哨兵型別 (類)
dangling	可能懸空的迭代器的包裝器 (類模板)
safe_iterator_t	將右值範圍的迭代器型別與 dangling 包裝的別名模板 (別名模板)
unreachable	與任何迭代器一起使用的哨兵型別，表示無限範圍 (類)

流迭代器

定義於名稱空間 std::experimental::ranges
istream_iterator	從std::basic_istream讀取的輸入迭代器 (類模板)
ostream_iterator	寫入std::basic_ostream的輸出迭代器 (類模板)
istreambuf_iterator	從std::basic_streambuf讀取的輸入迭代器 (類模板)
ostreambuf_iterator	寫入std::basic_streambuf的輸出迭代器 (類模板)

摘要

namespace std { namespace experimental { namespace ranges { inline namespace v1 {
 
template <class T> concept bool /* dereferenceable */ // exposition only
  = requires(T& t) { {*t} -> auto&&; };
 
namespace {
  constexpr /* unspecified */ iter_move = /* unspecified */;
  constexpr /* unspecified */ iter_swap = /* unspecified */;
}
 
template <class> struct difference_type;
template <class T> using difference_type_t
  = typename difference_type<T>::type;
 
template <class> struct value_type;
template <class T> using value_type_t
  = typename value_type<T>::type;
 
template <class> struct iterator_category;
template <class T> using iterator_category_t
  = typename iterator_category<T>::type;
 
template </* dereferenceable */ T> using reference_t
  = decltype(*declval<T&>());
 
template </* dereferenceable */ T>
    requires /* see definition */ using rvalue_reference_t
  = decltype(ranges::iter_move(declval<T&>()));
 
template <class In>
concept bool Readable = /* see definition */;
 
template <class Out, class T>
concept bool Writable = /* see definition */;
 
template <class I>
concept bool WeaklyIncrementable = /* see definition */;
 
template <class I>
concept bool Incrementable = /* see definition */;
 
template <class I>
concept bool Iterator = /* see definition */;
 
template <class S, class I>
concept bool Sentinel = /* see definition */;
 
template <class S, class I>
  constexpr bool disable_sized_sentinel = false;
 
template <class S, class I>
concept bool SizedSentinel = /* see definition */;
 
template <class I>
concept bool InputIterator = /* see definition */;
 
template <class I>
concept bool OutputIterator = /* see definition */;
 
template <class I>
concept bool ForwardIterator = /* see definition */;
 
template <class I>
concept bool BidirectionalIterator = /* see definition */;
 
template <class I>
concept bool RandomAccessIterator = /* see definition */;
 
template <class F, class I>
concept bool IndirectUnaryInvocable = /* see definition */;
 
template <class F, class I>
concept bool IndirectRegularUnaryInvocable = /* see definition */;
 
template <class F, class I>
concept bool IndirectUnaryPredicate = /* see definition */;
 
template <class F, class I1, class I2 = I1>
concept bool IndirectRelation = /* see definition */;
 
template <class F, class I1, class I2 = I1>
concept bool IndirectStrictWeakOrder = /* see definition */;
 
template <class> struct indirect_result_of;
 
template <class F, class... Is>
  requires Invocable<F, reference_t<Is>...>
struct indirect_result_of<F(Is...)>;
 
template <class F>
using indirect_result_of_t
  = typename indirect_result_of<F>::type;
 
template <Readable I, IndirectRegularUnaryInvocable<I> Proj>
struct projected;
 
template <WeaklyIncrementable I, class Proj>
struct difference_type<projected<I, Proj>>;
 
template <class In, class Out>
concept bool IndirectlyMovable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyMovableStorable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyCopyable = /* see definition */;
 
template <class In, class Out>
concept bool IndirectlyCopyableStorable = /* see definition */;
 
template <class I1, class I2 = I1>
concept bool IndirectlySwappable = /* see definition */;
 
template <class I1, class I2, class R = equal_to<>, class P1 = identity,
    class P2 = identity>
concept bool IndirectlyComparable = /* see definition */;
 
template <class I>
concept bool Permutable = /* see definition */;
 
template <class I1, class I2, class Out,
    class R = less<>, class P1 = identity, class P2 = identity>
concept bool Mergeable = /* see definition */;
 
template <class I, class R = less<>, class P = identity>
concept bool Sortable = /* see definition */;
 
template <class Iterator> using iterator_traits = /* see definition */;
 
template <Readable T> using iter_common_reference_t
  = common_reference_t<reference_t<T>, value_type_t<T>&>;
 
struct output_iterator_tag { };
struct input_iterator_tag { };
struct forward_iterator_tag : input_iterator_tag { };
struct bidirectional_iterator_tag : forward_iterator_tag { };
struct random_access_iterator_tag : bidirectional_iterator_tag { };
 
namespace {
  constexpr /* unspecified */ advance = /* unspecified */;
  constexpr /* unspecified */ distance = /* unspecified */;
  constexpr /* unspecified */ next = /* unspecified */;
  constexpr /* unspecified */ prev = /* unspecified */;
}
 
template <BidirectionalIterator I> class reverse_iterator;
 
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator==(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator!=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<=(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
 
template <class I1, class I2>
    requires SizedSentinel<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const reverse_iterator<I1>& x,
    const reverse_iterator<I2>& y);
template <RandomAccessIterator I>
  constexpr reverse_iterator<I> operator+(
    difference_type_t<I> n,
    const reverse_iterator<I>& x);
 
template <BidirectionalIterator I>
constexpr reverse_iterator<I> make_reverse_iterator(I i);
 
template <class Container> class back_insert_iterator;
template <class Container>
  back_insert_iterator<Container> back_inserter(Container& x);
 
template <class Container> class front_insert_iterator;
template <class Container>
  front_insert_iterator<Container> front_inserter(Container& x);
 
template <class Container> class insert_iterator;
template <class Container>
  insert_iterator<Container> inserter(Container& x, iterator_t<Container> i);
 
template <InputIterator I> class move_iterator;
 
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator==(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires EqualityComparableWith<I1, I2>
  constexpr bool operator!=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator<=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
template <class I1, class I2>
    requires StrictTotallyOrderedWith<I1, I2>
  constexpr bool operator>=(
    const move_iterator<I1>& x, const move_iterator<I2>& y);
 
template <class I1, class I2>
    requires SizedSentinel<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const move_iterator<I1>& x,
    const move_iterator<I2>& y);
template <RandomAccessIterator I>
  constexpr move_iterator<I> operator+(
    difference_type_t<I> n,
    const move_iterator<I>& x);
 
template <InputIterator I>
  constexpr move_iterator<I> make_move_iterator(I i);
 
template <Semiregular S> class move_sentinel;
 
template <class I, Sentinel<I> S>
  constexpr bool operator==(
    const move_iterator<I>& i, const move_sentinel<S>& s);
template <class I, Sentinel<I> S>
  constexpr bool operator==(
    const move_sentinel<S>& s, const move_iterator<I>& i);
template <class I, Sentinel<I> S>
  constexpr bool operator!=(
    const move_iterator<I>& i, const move_sentinel<S>& s);
template <class I, Sentinel<I> S>
  constexpr bool operator!=(
    const move_sentinel<S>& s, const move_iterator<I>& i);
 
template <class I, SizedSentinel<I> S>
  constexpr difference_type_t<I> operator-(
    const move_sentinel<S>& s, const move_iterator<I>& i);
template <class I, SizedSentinel<I> S>
  constexpr difference_type_t<I> operator-(
    const move_iterator<I>& i, const move_sentinel<S>& s);
 
template <Semiregular S>
  constexpr move_sentinel<S> make_move_sentinel(S s);
 
template <Iterator I, Sentinel<I> S>
  requires !Same<I, S>
class common_iterator;
 
template <Readable I, class S>
struct value_type<common_iterator<I, S>>;
 
template <InputIterator I, class S>
struct iterator_category<common_iterator<I, S>>;
 
template <ForwardIterator I, class S>
struct iterator_category<common_iterator<I, S>>;
 
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
bool operator==(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
  requires EqualityComparableWith<I1, I2>
bool operator==(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
template <class I1, class I2, Sentinel<I2> S1, Sentinel<I1> S2>
bool operator!=(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
 
template <class I2, SizedSentinel<I2> I1, SizedSentinel<I2> S1, SizedSentinel<I1> S2>
difference_type_t<I2> operator-(
  const common_iterator<I1, S1>& x, const common_iterator<I2, S2>& y);
 
class default_sentinel;
 
template <Iterator I> class counted_iterator;
 
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator==(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
constexpr bool operator==(
  const counted_iterator<auto>& x, default_sentinel);
constexpr bool operator==(
  default_sentinel, const counted_iterator<auto>& x);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator!=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
constexpr bool operator!=(
  const counted_iterator<auto>& x, default_sentinel y);
constexpr bool operator!=(
  default_sentinel x, const counted_iterator<auto>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator<(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator<=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator>(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr bool operator>=(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
 
template <class I1, class I2>
    requires Common<I1, I2>
  constexpr difference_type_t<I2> operator-(
    const counted_iterator<I1>& x, const counted_iterator<I2>& y);
template <class I>
  constexpr difference_type_t<I> operator-(
    const counted_iterator<I>& x, default_sentinel y);
template <class I>
  constexpr difference_type_t<I> operator-(
    default_sentinel x, const counted_iterator<I>& y);
template <RandomAccessIterator I>
  constexpr counted_iterator<I>
    operator+(difference_type_t<I> n, const counted_iterator<I>& x);
 
template <Iterator I>
  constexpr counted_iterator<I> make_counted_iterator(I i, difference_type_t<I> n);
 
class unreachable;
template <Iterator I>
  constexpr bool operator==(const I&, unreachable) noexcept;
template <Iterator I>
  constexpr bool operator==(unreachable, const I&) noexcept;
template <Iterator I>
  constexpr bool operator!=(const I&, unreachable) noexcept;
template <Iterator I>
  constexpr bool operator!=(unreachable, const I&) noexcept;
 
template <class T> class dangling;
 
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, class Traits, class Distance>
  bool operator==(default_sentinel 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,
    default_sentinel 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, class Traits, class Distance>
  bool operator!=(default_sentinel 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,
    default_sentinel 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>
  bool operator==(default_sentinel a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator==(const istreambuf_iterator<CharT, Traits>& a,
    default_sentinel 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>
  bool operator!=(default_sentinel a,
    const istreambuf_iterator<CharT, Traits>& b);
template <class CharT, class Traits>
  bool operator!=(const istreambuf_iterator<CharT, Traits>& a,
    default_sentinel b);
 
template <class CharT, class Traits = char_traits<CharT> >
  class ostreambuf_iterator;
 
}}}}
 
namespace std {
  template <experimental::ranges::Iterator Out>
    struct iterator_traits<Out>;
  template <experimental::ranges::InputIterator In>
    struct iterator_traits<In>;
  template <experimental::ranges::InputIterator In>
      requires experimental::ranges::Sentinel<In, In>
    struct iterator_traits;
}