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

💅 std::ranges..._view::size(3) — C++ Standard Libary energy ✨

Hey bestie, welcome to the C++ Standard Libary page for std::ranges..._view::size(3). No cap, this is the size member of std::ranges::adjacent_view, and she's here to tell you how many elements are in the house. 🫶

💅 NAME 💅

std::ranges::adjacent_view::size — std::ranges::adjacent_view::size. That's the name, bestie, it's giving “I repeat myself because that's literally the manpage NAME line.” 💀

✨ Synopsis ✨

Two overloads, both (since C++23), both constexpr, and both gated by a requires clause. Here's the exact signature tea:

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

Returns the number of elements. Let base_ be the underlying view. Equivalent to:

using SizeType = decltype(ranges::size(base_));
using CommonType = ranges::common_type_t<SizeType, std::size_t>;
auto size = static_cast<CommonType>(ranges::size(base_));
size -= std::min<CommonType>(size, N - 1);
return static_cast<SizeType>(size);

🎀 Parameters 🎀

(none) — she takes zero parameters. Nothing. Nada. Iconic minimalism. 🧚

🔥 Return value 🔥

The number of elements, may be 0 if ranges::size(base_) is less than N. So if the underlying range is too short, bestie can absolutely hand you a zero. No drama, just math. ✨

🌈 Example 🌈

The page says // Run this code, and here's the exact code, no edits, no cap:

#include <ranges>

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

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

    constexpr int width2 {8};
    constexpr auto view2 {std::views::adjacent<width2>(v)};
    // 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).

That's the whole page, bestie — slay, periodt, and may your size() always be sized. 💖

xoxo, your C++ bestie 💅 — source: http://cppreference.com, version/date: 2024.06.10, page: std::ranges..._view::size(3).