[range.repeat]

The name views::repeat denotes a customization point object ([customization.point.object]).

Given subexpressions E and F, the expressions views::repeat(E) and views::repeat(E, F) are expression-equivalent to repeat_view<decay_t<decltype(E))>(E) and repeat_view(E, F), respectively.

[Example 1: for (int i : views::repeat(17, 4) cout << i << ' '; / prints 17 17 17 17 — end example]

25.6.5.2 Class template repeat_view [range.repeat.view]

namespace std::ranges { template<class T> concept integer-like-with-usable-difference-type = / exposition only is-signed-integer-like<T> || (is-integer-like<T> && weakly_incrementable<T>); template<move_constructible T, semiregular Bound = unreachable_sentinel_t> requires (is_object_v<T> && same_as<T, remove_cv_t<T>> && (integer-like-with-usable-difference-type<Bound> || same_as<Bound, unreachable_sentinel_t>) class repeat_view : public view_interface<repeat_view<T, Bound>> { private: / [range.repeat.iterator], class repeat_view::iterator struct iterator; / exposition only movable-box<T> value_; / exposition only, see [range.move.wrap] Bound bound_ = Bound(); / exposition only public: repeat_view() requires default_initializable<T> = default; constexpr explicit repeat_view(const T& value, Bound bound = Bound() requires copy_constructible<T>; constexpr explicit repeat_view(T&& value, Bound bound = Bound(); template<class. TArgs, class. BoundArgs> requires constructible_from<T, TArgs..> && constructible_from<Bound, BoundArgs..> constexpr explicit repeat_view(piecewise_construct_t, tuple<TArgs..> value_args, tuple<BoundArgs..> bound_args = tuple<>{}); constexpr iterator begin() const; constexpr iterator end() const requires (!same_as<Bound, unreachable_sentinel_t>); constexpr unreachable_sentinel_t end() const noexcept; constexpr auto size() const requires (!same_as<Bound, unreachable_sentinel_t>); }; template<class T, class Bound = unreachable_sentinel_t> repeat_view(T, Bound = Bound() -> repeat_view<T, Bound>; }

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constexpr explicit repeat_view(const T& value, Bound bound = Bound()
  requires copy_constructible<T>;

Preconditions: If Bound is not unreachable_sentinel_t, bound ≥ 0.

Effects: Initializes value_ with value and bound_ with bound.

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constexpr explicit repeat_view(T&& value, Bound bound = Bound();

Effects: Initializes value_ with std::move(value) and bound_ with bound.

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template<class. TArgs, class. BoundArgs>
  requires constructible_from<T, TArgs..> &&
           constructible_from<Bound, BoundArgs..>
constexpr explicit repeat_view(piecewise_construct_t,
  tuple<TArgs..> value_args, tuple<BoundArgs..> bound_args = tuple<>{});

Effects: Initializes value_ with make_from_tuple<T>(std::move(value_args)) and initializes bound_ with make_from_tuple<Bound>(std::move(bound_args)).

The behavior is undefined if Bound is not unreachable_sentinel_t and bound_ is negative.

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constexpr iterator begin() const;

Effects: Equivalent to: return iterator(addressof(*value_);

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constexpr iterator end() const requires (!same_as<Bound, unreachable_sentinel_t>);

Effects: Equivalent to: return iterator(addressof(*value_), bound_);

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constexpr unreachable_sentinel_t end() const noexcept;

Effects: Equivalent to: return unreachable_sentinel;

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constexpr auto size() const requires (!same_as<Bound, unreachable_sentinel_t>);

Effects: Equivalent to: return to-unsigned-like(bound_);

25.6.5.3 Class repeat_view::iterator [range.repeat.iterator]

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namespace std::ranges { template<move_constructible T, semiregular Bound> requires (is_object_v<T> && same_as<T, remove_cv_t<T>> && (integer-like-with-usable-difference-type<Bound> || same_as<Bound, unreachable_sentinel_t>) class repeat_view<T, Bound>::iterator { private: using index-type = / exposition only conditional_t<same_as<Bound, unreachable_sentinel_t>, ptrdiff_t, Bound>; const T* value_ = nullptr; / exposition only index-type current_ = index-type(); / exposition only constexpr explicit iterator(const T* value, index-type b = index-type(); / exposition only public: using iterator_concept = random_access_iterator_tag; using iterator_category = random_access_iterator_tag; using value_type = T; using difference_type = see below; iterator() = default; constexpr const T& operator*() const noexcept; constexpr iterator& operator+(); constexpr iterator operator+(int); constexpr iterator& operator-(); constexpr iterator operator-(int); constexpr iterator& operator+=(difference_type n); constexpr iterator& operator-=(difference_type n); constexpr const T& operator[](difference_type n) const noexcept; friend constexpr bool operator=(const iterator& x, const iterator& y); friend constexpr auto operator<=>(const iterator& x, const iterator& y); friend constexpr iterator operator+(iterator i, difference_type n); friend constexpr iterator operator+(difference_type n, iterator i); friend constexpr iterator operator-(iterator i, difference_type n); friend constexpr difference_type operator-(const iterator& x, const iterator& y); }; }

If is-signed-integer-like<index-type> is true, the member typedef-name difference_type denotes index-type.

Otherwise, it denotes IOTA-DIFF-T(index-type) ([range.iota.view]).

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constexpr explicit iterator(const T* value, index-type b = index-type();

Effects: Initializes value_ with value and current_ with b.

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constexpr const T& operator*() const noexcept;

Effects: Equivalent to: return *value_;

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constexpr iterator& operator+();

Effects: Equivalent to: ++current_; return *this;

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constexpr iterator operator+(int);

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

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constexpr iterator& operator-();

Preconditions: If Bound is not unreachable_sentinel_t,

current_> 0 .

Effects: Equivalent to: --current_; return *this;

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constexpr iterator operator-(int);

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

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constexpr iterator& operator+=(difference_type n);

Preconditions: If Bound is not unreachable_sentinel_t,

current_+ n \geq 0 .

Effects: Equivalent to: current_ += n; return *this;

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constexpr iterator& operator-=(difference_type n);

Preconditions: If Bound is not unreachable_sentinel_t,

current_- n \geq 0 .

Effects: Equivalent to: current_ -= n; return *this;

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constexpr const T& operator[](difference_type n) const noexcept;

Effects: Equivalent to: return *(*this + n);

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

Effects: Equivalent to: return x.current_ == y.current_;

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friend constexpr auto operator<=>(const iterator& x, const iterator& y);

Effects: Equivalent to: return x.current_ <=> y.current_;

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friend constexpr iterator operator+(iterator i, difference_type n);
friend constexpr iterator operator+(difference_type n, iterator i);

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

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friend constexpr iterator operator-(iterator i, difference_type n);

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

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friend constexpr difference_type operator-(const iterator& x, const iterator& y);

Effects: Equivalent to: return static_cast<difference_type>(x.current_) - static_cast<difference_type>(y.current_);

25.6.5.2 Class template repeat_view [range.repeat.view]

25.6.5.3 Class repeat_view​::​iterator [range.repeat.iterator]

25.6.5.3 Class repeat_view::iterator [range.repeat.iterator]