std::ranges::views::repeat,std::ranges::repeat_view(3)

NAME
std::ranges::views::repeat,std::ranges::repeat_view - std::ranges::views::repeat,std::ranges::repeat_view

Synopsis
   Defined in header <ranges>
   template< std::move_constructible W,
             std::semiregular Bound = std::unreachable_sentinel_t >
       requires (std::is_object_v<W> && std::same_as<W,
   std::remove_cv_t<W>> && (1) (since C++23)
                (/*is-integer-like*/<Bound> ||
                 std::same_as<Bound, std::unreachable_sentinel_t>))
   class repeat_view : public ranges::view_interface<repeat_view<W,
   Bound>>
   namespace views {
       inline constexpr /*unspecified*/ repeat = /*unspecified*/; (2) (since C++23)
   }
   Call signature
   template< class W >
       requires /* see below */ (since C++23)
   constexpr /* see below */ repeat( W&& value );
   template< class W, class Bound >
       requires /* see below */ (since C++23)
   constexpr /* see below */ repeat( W&& value, Bound&& bound );
   1) A range factory that generates a sequence of elements by repeatedly producing the
   same value. Can be either bounded or unbounded (infinite).
   2) views::repeat(e) and views::repeat(e, f) are expression-equivalent to (has the
   same effect as) repeat_view(e) and repeat_view(e, f) respectively for any suitable
   subexpressions e and f.
   repeat_view models random_access_range. If Bound is not std::unreachable_sentinel_t,
   repeat_view also models sized_range and common_range.

Member functions
   constructor creates a repeat_view
                 (public member function)
   begin obtains the beginning iterator of a repeat_view
                 (public member function)
   end obtains the sentinel denoting the end of a repeat_view
                 (public member function)
   size obtains the size of a repeat_view if it is sized
                 (public member function)
         Inherited from std::ranges::view_interface
   empty returns whether the derived view is empty. Provided if it satisfies
   (C++20) sized_range or forward_range.
                 (public member function of std::ranges::view_interface<D>)
   cbegin returns a constant iterator to the beginning of the range.
   (C++23) (public member function of std::ranges::view_interface<D>)
   cend returns a sentinel for the constant iterator of the range.
   (C++23) (public member function of std::ranges::view_interface<D>)
   operator bool returns whether the derived view is not empty. Provided if
   (C++20) ranges::empty is applicable to it.
                 (public member function of std::ranges::view_interface<D>)
   front returns the first element in the derived view. Provided if it
   (C++20) satisfies forward_range.
                 (public member function of std::ranges::view_interface<D>)
   back returns the last element in the derived view. Provided if it satisfies
   (C++20) bidirectional_range and common_range.
                 (public member function of std::ranges::view_interface<D>)
   operator[] returns the n^th element in the derived view. Provided if it satisfies
   (C++20) random_access_range.
                 (public member function of std::ranges::view_interface<D>) std::ranges::repeat_view::repeat_view
   repeat_view() requires std::default_initializable<W> = default; (1) (since C++23)
   constexpr explicit repeat_view( const W& value, Bound bound = (2) (since C++23)
   Bound() );
   constexpr explicit repeat_view( W&& value, Bound bound = Bound() (3) (since C++23)
   );
   template < class... WArgs, class... BoundArgs >
       requires std::constructible_from<W, WArgs...>
             && std::constructible_from<Bound, BoundArgs...>
   constexpr explicit repeat( std::piecewise_construct_t, (4) (since C++23)
                        std::tuple<WArgs...> value_args,
                        std::tuple<BoundArgs...> bound_args =
   std::tuple<>{} );
   1) Value-initializes value_ and bound_ via their default member initializers (= W()
   and = Bound()).
   2) Initializes value_ with value and initializes bound_ with bound. The behavior is
   undefined if Bound is not std::unreachable_sentinel_t and bool(bound >= 0) is false.
   3) Initializes value_ with std::move(value) and initializes bound_ with bound. The
   behavior is undefined if Bound is not std::unreachable_sentinel_t and bool(bound >=
   0) is false.
   4) Initializes value_ and bound_ through piecewise construction.

Parameters
   value - the value to be repeatedly produced
   bound - the bound std::ranges::repeat_view::begin
   constexpr /*iterator*/ begin() const; (since C++23)
   Returns an iterator initialized with std::addressof(*value_). std::ranges::repeat_view::end
   constexpr /*iterator*/ end() const (1) (since C++23)
       requires (!std::same_as<Bound, std::unreachable_sentinel_t>);
   constexpr std::unreachable_sentinel_t end() const; (2) (since C++23)
   1) Returns an iterator initialized with std::addressof(*value_) and bound_.
   2) Returns an std::unreachable_sentinel. std::ranges::repeat_view::size
   constexpr auto size() const (since C++23)
       requires (!std::same_as<Bound, std::unreachable_sentinel_t>);
   Returns the size of the view if the view is bounded. Equivalent to return
   /*to-unsigned-like*/(bound_);.
   The exposition-only function template to-unsigned-like converts its argument (which
   must be integer-like) to the corresponding unsigned version of the argument type.
   Deduction guides
   template< class W, class Bound > (since C++23)
   repeat_view( W, Bound ) -> repeat_view<W, Bound>;
   Nested classes
   iterator the iterator type
   (C++23) (exposition-only member class*)

Notes
     Feature-test macro Value Std Feature
   __cpp_lib_ranges_repeat 202207L (C++23) std::ranges::repeat_view

Example
// Run this code
 #include <iostream>
 #include <ranges>
 #include <string_view>
 using namespace std::literals;
 int main()
 {
     // bounded overload
     for (auto s : std::views::repeat("C++"sv, 3))
         std::cout << s << ' ';
     std::cout << '\n';
     // unbounded overload
     for (auto s : std::views::repeat("I know that you know that"sv)
                 | std::views::take(3))
         std::cout << s << ' ';
     std::cout << "...\n";
 }

Output:
 C++ C++ C++
 I know that you know that I know that you know that I know that you know that ...

See also
   ranges::iota_view a view consisting of a sequence generated by repeatedly
   views::iota incrementing an initial value
   (C++20) (class template) (customization point object)