std::ranges..._view::size(3)

💖 NAME 💖

okay so welcome to the std::ranges..._view::size(3) page from the C++ Standard Libary (yes, that spelling is in the source, don't @ me 😭). The function bestie in the spotlight is:

std::ranges::adjacent_transform_view::size - std::ranges::adjacent_transform_view::size

Yes, it's listed twice. Iconic. Periodt. 👑

✨ Synopsis ✨

This is the whole synopsis, broken line and all, bestie — copy it exactly:

          constexpr auto size() requires ranges::sized_range<InnerView>;
       (since C++23)
          constexpr auto size() const requires ranges::sized_range<const
       (since C++23)
          InnerView>;

It returns the number of elements.

Let inner_ be the underlying object of type InnerView (that is the ranges::adjacent_view<V,N>).

1,2) Equivalent to return inner_.size();.

🎀 Parameters 🎀

(none) — literally zero parameters, bestie 🫶

🌈 Return value 🌈

The number of elements, may be 0 if the size of the underlying view V is less than N.

🍓 Example 🍓

// Run this code

#include <ranges>

int main()
{
    constexpr static auto v = {1, 2, 3, 4, 5, 6};

    auto f = [](auto...) { return 0; }; // dummy

    constexpr int width1 {4};
    constexpr auto view1 = v |
       std::views::adjacent_transform<width1>(f);
    static_assert(view1.size() == 3);
    static_assert(view1.size() == (v.size() - width1 + 1));

    constexpr int width2 {8};
    constexpr auto view2 = v |
       std::views::adjacent_transform<width2>(f);
    // window is too wide, so view2 has no elements:
    static_assert(view2.size() == 0);
}

🦋 See also 🦋

• ranges::size — returns an integer equal to the size of a range (C++20) (customization point object)
• ranges::ssize — returns a signed integer equal to the size of a range (C++20) (customization point object)

source/version: http://cppreference.com · date: 2024.06.10 — bye bestie, mwah 💜