cppdraft_translate/cppdraft/range/slide/iterator.md

[range.slide.iterator]

25 Ranges library [ranges]

25.7 Range adaptors [range.adaptors]

25.7.30 Slide view [range.slide]

25.7.30.3 Class template slide_view​::​iterator [range.slide.iterator]

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namespace std::ranges {template<forward_range V>requires viewtemplateclass slide_view::iterator {using Base = maybe-const<Const, V>; // exposition only iterator_t<Base> current_ = iterator_t<Base>(); // exposition only iterator_t<Base> last_ele_ = iterator_t<Base>(); // exposition only,// present only if Base models slide-caches-first range_difference_t<Base> n_ = 0; // exposition onlyconstexpr iterator(iterator_t<Base> current, range_difference_t<Base> n) // exposition onlyrequires (<Base>); constexpr iterator(iterator_t<Base> current, iterator_t<Base> last_ele, // exposition only range_difference_t<Base> n)requires slide-caches-first<Base>; public:using iterator_category = input_iterator_tag; using iterator_concept = see below; using value_type = decltype(views::counted(current_, n_)); using difference_type = range_difference_t<Base>; iterator() = default; constexpr iterator(iterator i)requires Const && convertible_to<iterator_t, iterator_t<Base>>; constexpr auto operator*() const; constexpr iterator& operator++(); constexpr iterator operator++(int); constexpr iterator& operator--() requires bidirectional_range<Base>; constexpr iterator operator--(int) requires bidirectional_range<Base>; constexpr iterator& operator+=(difference_type x)requires random_access_range<Base>; constexpr iterator& operator-=(difference_type x)requires random_access_range<Base>; constexpr auto operator[](difference_type n) constrequires random_access_range<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<Base>; friend constexpr bool operator>(const iterator& x, const iterator& y)requires random_access_range<Base>; friend constexpr bool operator<=(const iterator& x, const iterator& y)requires random_access_range<Base>; friend constexpr bool operator>=(const iterator& x, const iterator& y)requires random_access_range<Base>; friend constexpr auto operator<=>(const iterator& x, const iterator& y)requires random_access_range<Base> &&three_way_comparable<iterator_t<Base>>; friend constexpr iterator operator+(const iterator& i, difference_type n)requires random_access_range<Base>; friend constexpr iterator operator+(difference_type n, const iterator& i)requires random_access_range<Base>; friend constexpr iterator operator-(const iterator& i, difference_type n)requires random_access_range<Base>; friend constexpr difference_type operator-(const iterator& x, const iterator& y)requires sized_sentinel_for<iterator_t<Base>, iterator_t<Base>>; };}

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iterator​::​iterator_concept is defined as follows:

• (1.1)

  If Base models random_access_range, then iterator_concept denotes random_access_iterator_tag.

• (1.2)

  Otherwise, if Base models bidirectional_range, then iterator_concept denotes bidirectional_iterator_tag.

• (1.3)

  Otherwise, iterator_concept denotes forward_iterator_tag.

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If the invocation of any non-const member function of iterator exits via an exception, the iterator acquires a singular value.

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constexpr iterator(iterator_t<Base> current, range_difference_t<Base> n) requires (![slide-caches-first](range.slide.view#concept:slide-caches-first "25.7.30.2 Class template slide_­view [range.slide.view]")<Base>);

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Effects: Initializes current_ with current andn_ with n.

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constexpr iterator(iterator_t<Base> current, iterator_t<Base> last_ele, range_difference_t<Base> n) requires [slide-caches-first](range.slide.view#concept:slide-caches-first "25.7.30.2 Class template slide_­view [range.slide.view]")<Base>;

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Effects: Initializes current_ with current,last_ele_ with last_ele, andn_ with n.

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constexpr iterator(iterator<!Const> i) requires Const && [convertible_to](concept.convertible#concept:convertible_to "18.4.4 Concept convertible_­to [concept.convertible]")<iterator_t<V>, iterator_t<Base>>;

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Effects: Initializes current_ with std​::​move(i.current_) andn_ with i.n_.

[Note 1:

iterator can only be formed when Base models slide-caches-nothing, in which case last_ele_ is not present.

— end note]

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constexpr auto operator*() const;

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Returns: views​::​counted(current_, n_).

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constexpr iterator& operator++();

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Preconditions: current_ and last_ele_ (if present) are incrementable.

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Postconditions: current_ and last_ele_ (if present) are each equal to ranges​::​next(i), where i is the value of that data member before the call.

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Returns: *this.

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constexpr iterator operator++(int);

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Effects: Equivalent to:auto tmp = *this;++*this;return tmp;

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constexpr iterator& operator--() requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Preconditions: current_ and last_ele_ (if present) are decrementable.

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Postconditions: current_ and last_ele_ (if present) are each equal to ranges​::​prev(i), where i is the value of that data member before the call.

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Returns: *this.

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constexpr iterator operator--(int) requires [bidirectional_range](range.refinements#concept:bidirectional_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to:auto tmp = *this;--*this;return tmp;

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constexpr iterator& operator+=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Preconditions: current_ + x and last_ele_ + x (if last_ele_ is present) have well-defined behavior.

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Postconditions: current_ and last_ele_ (if present) are each equal to i + x, where i is the value of that data member before the call.

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Returns: *this.

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constexpr iterator& operator-=(difference_type x) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Preconditions: current_ - x and last_ele_ - x (if last_ele_ is present) have well-defined behavior.

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Postconditions: current_ and last_ele_ (if present) are each equal to i - x, where i is the value of that data member before the call.

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Returns: *this.

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constexpr auto operator[](difference_type n) const requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to: return views​::​counted(current_ + n, n_);

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friend constexpr bool operator==(const iterator& x, const iterator& y);

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Returns: If last_ele_ is present,x.last_ele_ == y.last_ele_; otherwise, x.current_ == y.current_.

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friend constexpr bool operator<(const iterator& x, const iterator& y) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Returns: x.current_ < y.current_.

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friend constexpr bool operator>(const iterator& x, const iterator& y) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to: return y < x;

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friend constexpr bool operator<=(const iterator& x, const iterator& y) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to: return !(y < x);

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friend constexpr bool operator>=(const iterator& x, const iterator& y) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to: return !(x < y);

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friend constexpr auto operator<=>(const iterator& x, const iterator& y) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base> && [three_way_comparable](cmp.concept#concept:three_way_comparable "17.12.4 Concept three_­way_­comparable [cmp.concept]")<iterator_t<Base>>;

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Returns: x.current_ <=> y.current_.

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friend constexpr iterator operator+(const iterator& i, difference_type n) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other 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 "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to:auto r = i; r += n;return r;

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friend constexpr iterator operator-(const iterator& i, difference_type n) requires [random_access_range](range.refinements#concept:random_access_range "25.4.6 Other range refinements [range.refinements]")<Base>;

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Effects: Equivalent to:auto r = i; r -= n;return r;

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friend constexpr difference_type operator-(const iterator& x, const iterator& y) requires [sized_sentinel_for](iterator.concept.sizedsentinel#concept:sized_sentinel_for "24.3.4.8 Concept sized_­sentinel_­for [iterator.concept.sizedsentinel]")<iterator_t<Base>, iterator_t<Base>>;

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Returns: If last_ele_ is present,x.last_ele_ - y.last_ele_; otherwise, x.current_ - y.current_.