std::ranges::cartesian_product_view<First, Vs...>:: end

From cppreference.com
C++
Ranges library
Range adaptors
std::ranges::cartesian_product_view
Member functions
cartesian_product_view::end
Deduction guides
Iterator
Member functions
Non-member functions
constexpr iterator < false > end ( )

requires ( ( ! /*simple-view*/ < First > || ... || ! /*simple-view*/ < Vs > ) &&

/*cartesian-product-is-common*/ < First, Vs... > ) ;
(1) (since C++23)
constexpr iterator < true > end ( ) const
requires /*cartesian-product-is-common*/ < const First, const Vs... > ;
(2) (since C++23)
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) Equivalent to
auto check = [ ] ( auto & rng ) { return __begin_or_first_end ( rng ) ; } ;
return iterator < __is_const > ( /*tuple-transform*/ ( check, bases_ ) ) ; ,
where:
  • __is_const is true for the const-qualified overload, and false otherwise.
  • __is_empty is true if the expression ranges:: empty ( rng ) is true for any rng among the underlying ranges except the first one and false otherwise.
  • __begin_or_first_end ( rng ) is 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.
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

returns an iterator to the beginning
(public member function)
(C++20)
returns a sentinel indicating the end of a range
(customization point object)
Retrieved from " https://en.cppreference.com/mwiki/index.php?title=cpp/ranges/cartesian_product_view/end&oldid=172750 "