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std::ranges...ke_view::end(3)  C++ Standard Libary std::ranges...ke_view::end(3)

NAME
     std::ranges::take_view::end - std::ranges::take_view::end

Synopsis
	constexpr  auto  end() requires (!__SimpleView<V>);	      (1) (since
     C++20)
	constexpr auto end() const requires ranges::range<const V>;  (2)  (since
     C++20)

	Returns a sentinel or an iterator representing the end of the take_view.
     The end of
	the  take_view is either one past the count-th element in the underlying
     range, or
	the end of the underlying range if the latter has less than  count  ele-
     ments.

	1)  Returns a take_view::/*sentinel*/<false>, a std::default_sentinel_t,
     or a
	ranges::iterator_t<V>.
	2) Returns a take_view::/*sentinel*/<true>,  a	std::default_sentinel_t,
     or a
	ranges::iterator_t<const V>.

	Overload  (1) does not participate in overload resolution if V is a sim-
     ple view (that
	is, if V and const V are views	with  the  same  iterator  and	sentinel
     types).

Parameters
	(none)

Return value
	The result depends on the concepts satisfied by possibly const-qualified
     underlying
	view  type  Base_, that is V (for overload (1)) or const V (for overload
     (2)).

	Let base_ be the underlying view.

	The underlying				 random_access_range
	view satisfies
	      ...							     yes
     no
			ranges::begin(base_) +
		    yes 						std::de-
     fault_sentinel
	sized_range	ranges::range_difference_t<Base_>(this->size())
		    no	1) /*sentinel*/<false>{ranges::end(base_)}
			2) /*sentinel*/<true>{ranges::end(base_)}

Example
     // Run this code

      #include <iostream>
      #include <iterator>
      #include <list>
      #include <ranges>
      #include <type_traits>

      int main()
      {
	  const auto list1 = {3, 1, 4, 1, 5};
	  const auto seq1 = list1 | std::views::take(4);
	  static_assert(std::ranges::sized_range<decltype(seq1)> &&
			std::ranges::random_access_range<decltype(seq1)> &&
			std::is_same_v<decltype(seq1.end()),		     de-
     cltype(list1.end())>);
	  for (auto it = seq1.begin(); it != seq1.end(); ++it)
	      std::cout << *it << ' ';
	  std::cout << '\n';

	  std::list list2 = {2, 7, 1, 8, 2};
	  const auto seq2 = list2 | std::views::take(4);
	  static_assert(std::ranges::sized_range<decltype(seq2)> &&
			not std::ranges::random_access_range<decltype(seq2)> &&
			std::is_same_v<decltype(seq2.end()),   std::default_sen-
     tinel_t>);
	  for (auto it = seq2.begin(); it != std::default_sentinel; ++it)
	      std::cout << *it << ' ';
	  std::cout << '\n';
      }

Output:
      3 1 4 1
      2 7 1 8

	Defect reports

	The  following	behavior-changing  defect  reports were applied retroac-
     tively to
	previously published C++ standards.

	  DR	Applied to		Behavior as published		    Cor-
     rect behavior
	P2393R1 C++20	   implicit conversions between signed and unsigned made
     explicit
			   integer-class types might fail

See also
	begin		 returns an iterator to the beginning
	(C++20) 	 (public member function)
	counted_iterator iterator adaptor that tracks the distance to the end of
     the range
	(C++20) 	 (class template)
	operator==	 compares a sentinel  with  an	iterator  returned  from
     take_view::begin
	(C++20) 	 (function)

http://cppreference.com 	   2024.06.10	   std::ranges...ke_view::end(3)
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