std::ranges...t_view::end(3)

💖 std::ranges::cartesian_product_view::end 💖

okay so this page is straight outta the C++ Standard Libary manual, and the page itself calls her std::ranges...t_view::end(3). yes, the header truncates the name like that. we move.

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🌸 NAME 🌸

std::ranges::cartesian_product_view::end — std::ranges::cartesian_product_view::end

(yes, the NAME section is literally her name twice. iconic behavior. 💅)

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✨ SYNOPSIS ✨

okay bestie, here are the three overloads, and they’re all since C++23. the (1), (2), and (3) bits are overload labels, not part of the C++ syntax vibe check.

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)

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🫶 DESCRIPTION 🫶

Returns an iterator or a sentinel representing the end of the cartesian_product_view. that’s the whole plot, bestie.

Let bases_ be the underlying tuple of views.

💅 1,2) the iterator overloads

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 otherwise; 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) the sentinel overload

Equivalent to: return std::default_sentinel;.

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🎀 PARAMETERS 🎀

(none) — literally no parameters, bestie. none. zero. the void is the vibe. 🫥

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🦋 RETURN VALUE 🦋

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

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🌈 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');
}

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🍓 OUTPUT 🍓

long

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💜 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)

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okay that’s the whole page, bestie. source/version/date tea: http://cppreference.com, 2024.06.10, and the footer page is std::ranges...t_view::end(3). mwah 💋✨