Files
2025-10-25 03:02:53 +03:00

353 lines
26 KiB
Markdown
Raw Permalink Blame History

This file contains invisible Unicode characters

This file contains invisible Unicode characters that are indistinguishable to humans but may be processed differently by a computer. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

[range.adjacent.transform]
# 25 Ranges library [[ranges]](./#ranges)
## 25.7 Range adaptors [[range.adaptors]](range.adaptors#range.adjacent.transform)
### 25.7.28 Adjacent transform view [range.adjacent.transform]
#### [25.7.28.1](#overview) Overview [[range.adjacent.transform.overview]](range.adjacent.transform.overview)
[1](#overview-1)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13226)
adjacent_transform_view takes an invocable object and
a view and produces a view
whose Mth element is the result of applying the invocable object
to the Mth through (M+N−1)th elements
of the original view[.](#overview-1.sentence-1)
If the original view has fewer than N elements, the resulting view is empty[.](#overview-1.sentence-2)
[2](#overview-2)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13234)
The name views::adjacent_transform<N> denotes
a range adaptor object ([[range.adaptor.object]](range.adaptor.object "25.7.2Range adaptor objects"))[.](#overview-2.sentence-1)
Given subexpressions E and F and
a constant expression N:
- [(2.1)](#overview-2.1)
If N is equal to 0 anddecltype((E)) models [forward_range](range.refinements#concept:forward_range "25.4.6Other range refinements[range.refinements]"),views::adjacent_transform<N>(E, F) is expression-equivalent to((void)E, views::zip_transform(F)),
except that the evaluations of E and F are
indeterminately sequenced[.](#overview-2.1.sentence-1)
- [(2.2)](#overview-2.2)
Otherwise,
the expression views::adjacent_transform<N>(E, F) is
expression-equivalent toadjacent_transform_view<views::all_t<decltype((E))>, decay_t<decltype((F))>, N>(E, F)[.](#overview-2.2.sentence-1)
[3](#overview-3)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13255)
[*Example [1](#overview-example-1)*: vector v = {1, 2, 3, 4};
for (auto i : v | views::adjacent_transform<2>(std::multiplies())) { cout << i << ' '; // prints 2 6 12} — *end example*]
#### [25.7.28.2](#view) Class template adjacent_transform_view [[range.adjacent.transform.view]](range.adjacent.transform.view)
[🔗](#lib:adjacent_transform_view)
namespace std::ranges {template<[forward_range](range.refinements#concept:forward_range "25.4.6Other range refinements[range.refinements]") V, [move_constructible](concept.moveconstructible#concept:move_constructible "18.4.13Concept move_­constructible[concept.moveconstructible]") F, size_t N>requires [view](range.view#concept:view "25.4.5Views[range.view]")<V> && (N > 0) && is_object_v<F> &&[regular_invocable](concept.regularinvocable#concept:regular_invocable "18.7.3Concept regular_­invocable[concept.regularinvocable]")<F&, *REPEAT*(range_reference_t<V>, N)...> &&[*can-reference*](iterator.synopsis#concept:can-reference "24.2Header <iterator>&nbsp;synopsis[iterator.synopsis]")<invoke_result_t<F&, *REPEAT*(range_reference_t<V>, N)...>>class adjacent_transform_view : public view_interface<adjacent_transform_view<V, F, N>> {*movable-box*<F> *fun_*; // *exposition only* adjacent_view<V, N> *inner_*; // *exposition only*using *InnerView* = adjacent_view<V, N>; // *exposition only*template<bool Const>using *inner-iterator* = iterator_t<*maybe-const*<Const, *InnerView*>>; // *exposition only*template<bool Const>using *inner-sentinel* = sentinel_t<*maybe-const*<Const, *InnerView*>>; // *exposition only*// [[range.adjacent.transform.iterator]](#iterator "25.7.28.3Class template adjacent_­transform_­view::iterator"), class template adjacent_transform_view::*iterator*template<bool> class *iterator*; // *exposition only*// [[range.adjacent.transform.sentinel]](#sentinel "25.7.28.4Class template adjacent_­transform_­view::sentinel"), class template adjacent_transform_view::*sentinel*template<bool> class *sentinel*; // *exposition only*public: adjacent_transform_view() = default; constexpr explicit adjacent_transform_view(V base, F fun); constexpr V base() const & requires [copy_constructible](concept.copyconstructible#concept:copy_constructible "18.4.14Concept copy_­constructible[concept.copyconstructible]")<V> { return *inner_*.base(); }constexpr V base() && { return std::move(*inner_*).base(); }constexpr auto begin() {return *iterator*<false>(*this, *inner_*.begin()); }constexpr auto begin() constrequires [range](range.range#concept:range "25.4.2Ranges[range.range]")<const *InnerView*> &&[regular_invocable](concept.regularinvocable#concept:regular_invocable "18.7.3Concept regular_­invocable[concept.regularinvocable]")<const F&, *REPEAT*(range_reference_t<const V>, N)...> {return *iterator*<true>(*this, *inner_*.begin()); }constexpr auto end() {if constexpr ([common_range](range.refinements#concept:common_range "25.4.6Other range refinements[range.refinements]")<*InnerView*>) {return *iterator*<false>(*this, *inner_*.end()); } else {return *sentinel*<false>(*inner_*.end()); }}constexpr auto end() constrequires [range](range.range#concept:range "25.4.2Ranges[range.range]")<const *InnerView*> &&[regular_invocable](concept.regularinvocable#concept:regular_invocable "18.7.3Concept regular_­invocable[concept.regularinvocable]")<const F&, *REPEAT*(range_reference_t<const V>, N)...> {if constexpr ([common_range](range.refinements#concept:common_range "25.4.6Other range refinements[range.refinements]")<const *InnerView*>) {return *iterator*<true>(*this, *inner_*.end()); } else {return *sentinel*<true>(*inner_*.end()); }}constexpr auto size() requires [sized_range](range.sized#concept:sized_range "25.4.4Sized ranges[range.sized]")<*InnerView*> {return *inner_*.size(); }constexpr auto size() const requires [sized_range](range.sized#concept:sized_range "25.4.4Sized ranges[range.sized]")<const *InnerView*> {return *inner_*.size(); }constexpr auto reserve_hint() requires [approximately_sized_range](range.approximately.sized#concept:approximately_sized_range "25.4.3Approximately sized ranges[range.approximately.sized]")<*InnerView*> {return *inner_*.reserve_hint(); }constexpr auto reserve_hint() const requires [approximately_sized_range](range.approximately.sized#concept:approximately_sized_range "25.4.3Approximately sized ranges[range.approximately.sized]")<const *InnerView*> {return *inner_*.reserve_hint(); }};}
[🔗](#lib:adjacent_transform_view,constructor)
`constexpr explicit adjacent_transform_view(V base, F fun);
`
[1](#view-1)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13356)
*Effects*: Initializes *fun_* with std::move(fun) and*inner_* with std::move(base)[.](#view-1.sentence-1)
#### [25.7.28.3](#iterator) Class template adjacent_transform_view::*iterator* [[range.adjacent.transform.iterator]](range.adjacent.transform.iterator)
[🔗](#lib:adjacent_transform_view::iterator)
namespace std::ranges {template<[forward_range](range.refinements#concept:forward_range "25.4.6Other range refinements[range.refinements]") V, [move_constructible](concept.moveconstructible#concept:move_constructible "18.4.13Concept move_­constructible[concept.moveconstructible]") F, size_t N>requires [view](range.view#concept:view "25.4.5Views[range.view]")<V> && (N > 0) && is_object_v<F> &&[regular_invocable](concept.regularinvocable#concept:regular_invocable "18.7.3Concept regular_­invocable[concept.regularinvocable]")<F&, *REPEAT*(range_reference_t<V>, N)...> &&[*can-reference*](iterator.synopsis#concept:can-reference "24.2Header <iterator>&nbsp;synopsis[iterator.synopsis]")<invoke_result_t<F&, *REPEAT*(range_reference_t<V>, N)...>>template<bool Const>class adjacent_transform_view<V, F, N>::*iterator* {using *Parent* = *maybe-const*<Const, adjacent_transform_view>; // *exposition only*using *Base* = *maybe-const*<Const, V>; // *exposition only**Parent** *parent_* = nullptr; // *exposition only**inner-iterator*<Const> *inner_*; // *exposition only*constexpr *iterator*(*Parent*& parent, *inner-iterator*<Const> inner); // *exposition only*public:using iterator_category = *see below*; using iterator_concept = typename *inner-iterator*<Const>::iterator_concept; using value_type = remove_cvref_t<invoke_result_t<*maybe-const*<Const, F>&, *REPEAT*(range_reference_t<*Base*>, N)...>>; using difference_type = range_difference_t<*Base*>; *iterator*() = default; constexpr *iterator*(*iterator*<!Const> i)requires Const && [convertible_to](concept.convertible#concept:convertible_to "18.4.4Concept convertible_­to[concept.convertible]")<*inner-iterator*<false>, *inner-iterator*<Const>>; constexpr decltype(auto) operator*() const noexcept(*see below*); constexpr *iterator*& operator++(); constexpr *iterator* operator++(int); constexpr *iterator*& operator--() requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6Other range refinements[range.refinements]")<*Base*>; constexpr *iterator* operator--(int) requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6Other range refinements[range.refinements]")<*Base*>; constexpr *iterator*& operator+=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; constexpr *iterator*& operator-=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; constexpr decltype(auto) operator[](difference_type n) constrequires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr bool operator==(const *iterator*& x, const *iterator*& y); friend constexpr bool operator<(const *iterator*& x, const *iterator*& y)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr bool operator>(const *iterator*& x, const *iterator*& y)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr bool operator<=(const *iterator*& x, const *iterator*& y)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr bool operator>=(const *iterator*& x, const *iterator*& y)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr auto operator<=>(const *iterator*& x, const *iterator*& y)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*> && [three_way_comparable](cmp.concept#concept:three_way_comparable "17.12.4Concept three_­way_­comparable[cmp.concept]")<*inner-iterator*<Const>>; friend constexpr *iterator* operator+(const *iterator*& i, difference_type n)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr *iterator* operator+(difference_type n, const *iterator*& i)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr *iterator* operator-(const *iterator*& i, difference_type n)requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<*Base*>; friend constexpr difference_type operator-(const *iterator*& x, const *iterator*& y)requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<*inner-iterator*<Const>, *inner-iterator*<Const>>; };}
[1](#iterator-1)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13427)
The member [*typedef-name*](dcl.typedef#nt:typedef-name "9.2.4The typedef specifier[dcl.typedef]") *iterator*::iterator_category is defined as follows:
- [(1.1)](#iterator-1.1)
If invoke_result_t<*maybe-const*<Const, F>&,*REPEAT*(range_reference_t<*Base*>, N)...> is not a reference,iterator_category denotes input_iterator_tag[.](#iterator-1.1.sentence-1)
- [(1.2)](#iterator-1.2)
Otherwise, let C denote the typeiterator_traits<iterator_t<*Base*>>::iterator_category[.](#iterator-1.2.sentence-1)
* [(1.2.1)](#iterator-1.2.1)
If [derived_from](concept.derived#concept:derived_from "18.4.3Concept derived_­from[concept.derived]")<C, random_access_iterator_tag> is true,iterator_category denotes random_access_iterator_tag[.](#iterator-1.2.1.sentence-1)
* [(1.2.2)](#iterator-1.2.2)
Otherwise,
if [derived_from](concept.derived#concept:derived_from "18.4.3Concept derived_­from[concept.derived]")<C, bidirectional_iterator_tag> is true,iterator_category denotes bidirectional_iterator_tag[.](#iterator-1.2.2.sentence-1)
* [(1.2.3)](#iterator-1.2.3)
Otherwise,
if [derived_from](concept.derived#concept:derived_from "18.4.3Concept derived_­from[concept.derived]")<C, forward_iterator_tag> is true,iterator_category denotes forward_iterator_tag[.](#iterator-1.2.3.sentence-1)
* [(1.2.4)](#iterator-1.2.4)
Otherwise, iterator_category denotes input_iterator_tag[.](#iterator-1.2.4.sentence-1)
[🔗](#lib:adjacent_transform_view::iterator,constructor)
`constexpr iterator(Parent& parent, inner-iterator<Const> inner);
`
[2](#iterator-2)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13465)
*Effects*: Initializes *parent_* with addressof(parent) and*inner_* with std::move(inner)[.](#iterator-2.sentence-1)
[🔗](#lib:adjacent_transform_view::iterator,constructor_)
`constexpr iterator(iterator<!Const> i)
requires Const && [convertible_to](concept.convertible#concept:convertible_to "18.4.4Concept convertible_­to[concept.convertible]")<inner-iterator<false>, inner-iterator<Const>>;
`
[3](#iterator-3)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13478)
*Effects*: Initializes *parent_* with i.*parent_* and*inner_* with std::move(i.*inner_*)[.](#iterator-3.sentence-1)
[🔗](#lib:operator*,adjacent_transform_view::iterator)
`constexpr decltype(auto) operator*() const noexcept(see below);
`
[4](#iterator-4)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13490)
*Effects*: Equivalent to:return apply([&](const auto&... iters) -> decltype(auto) {return invoke(**parent_*->*fun_*, *iters...);}, *inner_*.*current_*);
[5](#iterator-5)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13499)
*Remarks*: Let Is be the pack 0, 1, …, (N - 1)[.](#iterator-5.sentence-1)
The exception specification is equivalent to:noexcept(invoke(**parent_*->*fun_*, *std::get<Is>(*inner_*.*current_*)...))
[🔗](#lib:operator++,adjacent_transform_view::iterator)
`constexpr iterator& operator++();
`
[6](#iterator-6)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13514)
*Effects*: Equivalent to:++*inner_*;return *this;
[🔗](#lib:operator++,adjacent_transform_view::iterator_)
`constexpr iterator operator++(int);
`
[7](#iterator-7)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13529)
*Effects*: Equivalent to:auto tmp = *this;++*this;return tmp;
[🔗](#lib:operator--,adjacent_transform_view::iterator)
`constexpr iterator& operator--() requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[8](#iterator-8)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13545)
*Effects*: Equivalent to:--*inner_*;return *this;
[🔗](#lib:operator--,adjacent_transform_view::iterator_)
`constexpr iterator operator--(int) requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[9](#iterator-9)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13560)
*Effects*: Equivalent to:auto tmp = *this;--*this;return tmp;
[🔗](#lib:operator+=,adjacent_transform_view::iterator)
`constexpr iterator& operator+=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[10](#iterator-10)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13576)
*Effects*: Equivalent to:*inner_* += x;return *this;
[🔗](#lib:operator-=,adjacent_transform_view::iterator)
`constexpr iterator& operator-=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[11](#iterator-11)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13591)
*Effects*: Equivalent to:*inner_* -= x;return *this;
[🔗](#lib:operator%5b%5d,adjacent_transform_view::iterator)
`constexpr decltype(auto) operator[](difference_type n) const
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[12](#iterator-12)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13607)
*Effects*: Equivalent to:return apply([&](const auto&... iters) -> decltype(auto) {return invoke(**parent_*->*fun_*, iters[n]...);}, *inner_*.*current_*);
[🔗](#lib:operator==,adjacent_transform_view::iterator)
`friend constexpr bool operator==(const iterator& x, const iterator& y);
friend constexpr bool operator<(const iterator& x, const iterator& y)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
friend constexpr bool operator>(const iterator& x, const iterator& y)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
friend constexpr bool operator<=(const iterator& x, const iterator& y)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
friend constexpr bool operator>=(const iterator& x, const iterator& y)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
friend constexpr auto operator<=>(const iterator& x, const iterator& y)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base> && [three_way_comparable](cmp.concept#concept:three_way_comparable "17.12.4Concept three_­way_­comparable[cmp.concept]")<inner-iterator<Const>>;
`
[13](#iterator-13)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13633)
Let *op* be the operator[.](#iterator-13.sentence-1)
[14](#iterator-14)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13636)
*Effects*: Equivalent to: return x.*inner_* *op* y.*inner_*;
[🔗](#lib:operator+,adjacent_transform_view::iterator)
`friend constexpr iterator operator+(const iterator& i, difference_type n)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
friend constexpr iterator operator+(difference_type n, const iterator& i)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[15](#iterator-15)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13650)
*Effects*: Equivalent to: return *iterator*(*i.*parent_*, i.*inner_* + n);
[🔗](#lib:operator-,adjacent_transform_view::iterator)
`friend constexpr iterator operator-(const iterator& i, difference_type n)
requires [random_access_range](range.refinements#concept:random_access_range "25.4.6Other range refinements[range.refinements]")<Base>;
`
[16](#iterator-16)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13662)
*Effects*: Equivalent to: return *iterator*(*i.*parent_*, i.*inner_* - n);
[🔗](#lib:operator-,adjacent_transform_view::iterator_)
`friend constexpr difference_type operator-(const iterator& x, const iterator& y)
requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<inner-iterator<Const>, inner-iterator<Const>>;
`
[17](#iterator-17)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13674)
*Effects*: Equivalent to: return x.*inner_* - y.*inner_*;
#### [25.7.28.4](#sentinel) Class template adjacent_transform_view::*sentinel* [[range.adjacent.transform.sentinel]](range.adjacent.transform.sentinel)
[🔗](#lib:adjacent_transform_view::sentinel)
namespace std::ranges {template<[forward_range](range.refinements#concept:forward_range "25.4.6Other range refinements[range.refinements]") V, [move_constructible](concept.moveconstructible#concept:move_constructible "18.4.13Concept move_­constructible[concept.moveconstructible]") F, size_t N>requires [view](range.view#concept:view "25.4.5Views[range.view]")<V> && (N > 0) && is_object_v<F> &&[regular_invocable](concept.regularinvocable#concept:regular_invocable "18.7.3Concept regular_­invocable[concept.regularinvocable]")<F&, *REPEAT*(range_reference_t<V>, N)...> &&[*can-reference*](iterator.synopsis#concept:can-reference "24.2Header <iterator>&nbsp;synopsis[iterator.synopsis]")<invoke_result_t<F&, *REPEAT*(range_reference_t<V>, N)...>>template<bool Const>class adjacent_transform_view<V, F, N>::*sentinel* {*inner-sentinel*<Const> *inner_*; // *exposition only*constexpr explicit *sentinel*(*inner-sentinel*<Const> inner); // *exposition only*public:*sentinel*() = default; constexpr *sentinel*(*sentinel*<!Const> i)requires Const && [convertible_to](concept.convertible#concept:convertible_to "18.4.4Concept convertible_­to[concept.convertible]")<*inner-sentinel*<false>, *inner-sentinel*<Const>>; template<bool OtherConst>requires [sentinel_for](iterator.concept.sentinel#concept:sentinel_for "24.3.4.7Concept sentinel_­for[iterator.concept.sentinel]")<*inner-sentinel*<Const>, *inner-iterator*<OtherConst>>friend constexpr bool operator==(const *iterator*<OtherConst>& x, const *sentinel*& y); template<bool OtherConst>requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<*inner-sentinel*<Const>, *inner-iterator*<OtherConst>>friend constexpr range_difference_t<*maybe-const*<OtherConst, *InnerView*>>operator-(const *iterator*<OtherConst>& x, const *sentinel*& y); template<bool OtherConst>requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<*inner-sentinel*<Const>, *inner-iterator*<OtherConst>>friend constexpr range_difference_t<*maybe-const*<OtherConst, *InnerView*>>operator-(const *sentinel*& x, const *iterator*<OtherConst>& y); };}
[🔗](#lib:adjacent_transform_view::sentinel,constructor)
`constexpr explicit sentinel(inner-sentinel<Const> inner);
`
[1](#sentinel-1)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13721)
*Effects*: Initializes *inner_* with inner[.](#sentinel-1.sentence-1)
[🔗](#lib:adjacent_transform_view::sentinel,constructor_)
`constexpr sentinel(sentinel<!Const> i)
requires Const && [convertible_to](concept.convertible#concept:convertible_to "18.4.4Concept convertible_­to[concept.convertible]")<inner-sentinel<false>, inner-sentinel<Const>>;
`
[2](#sentinel-2)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13733)
*Effects*: Initializes *inner_* with std::move(i.*inner_*)[.](#sentinel-2.sentence-1)
[🔗](#lib:operator==,adjacent_transform_view::sentinel)
`template<bool OtherConst>
requires [sentinel_for](iterator.concept.sentinel#concept:sentinel_for "24.3.4.7Concept sentinel_­for[iterator.concept.sentinel]")<inner-sentinel<Const>, inner-iterator<OtherConst>>
friend constexpr bool operator==(const iterator<OtherConst>& x, const sentinel& y);
`
[3](#sentinel-3)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13746)
*Effects*: Equivalent to: return x.*inner_* == y.*inner_*;
[🔗](#lib:operator-,adjacent_transform_view::sentinel)
`template<bool OtherConst>
requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<inner-sentinel<Const>, inner-iterator<OtherConst>>
friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
operator-(const iterator<OtherConst>& x, const sentinel& y);
template<bool OtherConst>
requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8Concept sized_­sentinel_­for[iterator.concept.sizedsentinel]")<inner-sentinel<Const>, inner-iterator<OtherConst>>
friend constexpr range_difference_t<maybe-const<OtherConst, InnerView>>
operator-(const sentinel& x, const iterator<OtherConst>& y);
`
[4](#sentinel-4)
[#](http://github.com/Eelis/draft/tree/9adde4bc1c62ec234483e63ea3b70a59724c745a/source/ranges.tex#L13765)
*Effects*: Equivalent to: return x.*inner_* - y.*inner_*;