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

✨ NAME ✨

okay bestie, welcome to std::ranges..._view::size(3) from the C++ Standard Libary manual (that's the header's spelling, not mine 💀) — today's main character is std::ranges::stride_view::size, aka the size member of std::ranges::stride_view, and she has two constexpr overloads and a whole lot of math energy ✨

🎀 SYNOPSIS 🎀

• constexpr auto size() requires ranges::sized_range<V>; — since C++23 🫶
• constexpr auto size() const requires ranges::sized_range<const V>; — since C++23 🫶

She returns the number of elements, periodt.

Let base_ be the underlying view and stride_ be the stored stride value. Equivalent to:

return __to_unsigned_like(__div_ceil(ranges::distance(base_),
       stride_));

🌸 PARAMETERS 🌸

Nope, none. Not a single parameter. She's low-maintenance like that 💅

💖 RETURN VALUE 💖

The number of elements. The returned value is calculated as if by expression:

(ranges::size(base_) / stride_) + ((ranges::size(base_) % stride_ ? 1 : 0).

copying that exactly, bestie 🫶

🧚 EXAMPLE 🧚

// Run this code

#include <forward_list>
#include <ranges>

int main()
{
    namespace vs = std::views;
    constexpr static auto v = {1, 2, 3, 4, 5};
    static_assert
    (
        vs::stride(v, 1).size() == 5 and
        vs::stride(v, 2).size() == 3 and
        vs::stride(v, 3).size() == 2 and
        vs::stride(v, 4).size() == 2 and
        vs::stride(v, 5).size() == 1 and
        vs::stride(v, 6).size() == 1
    );

    std::forward_list list{v};
//  auto s = vs::stride(list, 2).size(); // Error: not a sized_range
}

🦋 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) 👑

that's the tea: source http://cppreference.com, dated 2024.06.10, and this iconic page is std::ranges..._view::size(3). byeee 💅🎀