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std::ranges::concat_view<Views...>::end

From cppreference.com
< cpp‎ | ranges‎ | concat view
 
C++
 
Ranges library
Range adaptors
 
std::ranges::concat_view
constexpr auto end()
    requires (!(/*simple-view*/<Views> && ...));
(1) (since C++26)
constexpr auto end() const

    requires (ranges::range<const Views> && ...) &&

                 /*concatable*/<const Views...>;
(2) (since C++26)

Returns an iterator or std::default_sentinel that compares equal to the past-the-end iterator of the concat_view.

1) Equivalent to

constexpr auto N = sizeof...(Views);
if constexpr (ranges::common_range<Views...[N - 1]>)
    return iterator <false>(this, std::in_place_index<N - 1>,
                           ranges::end(std::get<N - 1>(views_ ));
else
    return std::default_sentinel;

.
2) Equivalent to

constexpr auto N = sizeof...(Views);
if constexpr (ranges::common_range<const Views...[N - 1]>)
    return iterator <true>(this, std::in_place_index<N - 1>,
                          ranges::end(std::get<N - 1>(views_ ));
else
    return std::default_sentinel;

.

[edit] Return value

As described above.

[edit] Example

The preliminary version can be checked out on Compiler Explorer.

#include <concepts>
#include <iterator>
#include <ranges>
 
int main()
{
    static constexpr int p[]{37, 42, 69};
    static constexpr auto q = {19937, 1729};
    constexpr auto cat = std::ranges::views::concat(p, q);
    static_assert(not std::same_as<std::default_sentinel_t, decltype(cat.end()>);
    static_assert(cat.end()[-1] == 1729);
}

[edit] See also

returns an iterator to the beginning
(public member function) [edit]
returns a sentinel indicating the end of a range
(customization point object)[edit]

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