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

NAME
       std::ranges::cartesian_product_view::end	- std::ranges::cartesian_prod-
       uct_view::end

Synopsis
	  constexpr iterator<false> end()

	      requires	((!__simple_view<First>	 || ...	|| !__simple_view<Vs>)
       (1) (since C++23)
	  &&

		  __cartesian_product_is_common<First, Vs...>);
	  constexpr iterator<true> end() const
	      requires	 __cartesian_product_is_common<const   First,	 const
       (2) (since C++23)
	  Vs...>;
	  constexpr	std::default_sentinel_t	   end()    const    noexcept;
       (3) (since C++23)

	  Returns an iterator or a sentinel representing the end of the
	  cartesian_product_view.

	  Let bases_ be	the underlying tuple of	views.

	  1,2) Let:
	    * __is_const be true for the const-qualified overload,  and	 false
       otherwise;
	    *  __is_empty be true if the expression ranges::empty(rng) is true
       for any rng
	      among the	underlying ranges except the first one and false  oth-
       erwise; and
	    * __begin_or_first_end(rng)	be expression-equivalent to __is_empty
       ?
	      ranges::begin(rng)  :  __cartesian_common_arg_end(rng) if	rng is
       the first
	      underlying range and ranges::begin(rng) otherwise.

	  Equivalent to:

	auto check = [](auto& rng) { return __begin_or_first_end(rng); };
	return iterator<__is_const>(__tuple_transform(check, bases_));

	  3) Equivalent	to: return std::default_sentinel;.

Parameters
	  (none)

Return value
	  An iterator to the element following the last	element, or a sentinel
       which compares
	  equal	to the end iterator.

Example
       // Run this code

	#include <array>
	#include <format>
	#include <iostream>
	#include <ranges>
	#include <string_view>
	#include <tuple>
	using namespace	std::literals;

	int main()
	{
	    constexpr auto a =	std::array{  "bool"sv,	"goto"sv,  "extern"sv,
       "long"sv	}; /*
					       ^	     ^		     ^
       ^	*/
	    constexpr auto v = std::ranges::cartesian_product_view(a[0], a[1],
       a[2], a[3]);

	    constexpr std::tuple<char const&,
				 char const&,
				 char const&,
				 char const&> last{*(v.end() - 1)};

	    std::cout << std::format("{}{}{}{}{}",
				     std::get<0>(last),
				     std::get<1>(last),
				     std::get<2>(last),
				     std::get<3>(last),	'\n');
	}

Output:
	long

See also
	  begin	      returns an iterator to the beginning
	  (C++23)     (public member function)
	  ranges::end returns a	sentinel indicating the	end of a range
	  (C++20)     (customization point object)

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

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