std::ranges...ccess_range(3)

hey bestie 💖 this is the std::ranges...ccess_range(3) page from the C++ Standard Libary manual — yes, that exact spelling, we don’t gatekeep typos here 🫶

🌸 NAME 🌸

std::ranges::random_access_range - std::ranges::random_access_range

✨ Synopsis ✨

Defined in header <ranges>

Defined in header <ranges>
template< class T >
concept random_access_range =
    ranges::bidirectional_range<T> &&
std::random_access_iterator<ranges::iterator_t<T>>;

(since C++20)

The random_access_range concept is a refinement of range for which ranges::begin returns a model of random_access_iterator. It’s giving “range but make it random-access” energy 👑

🦋 Example 🦋

// Run this code

#include <array>
#include <deque>
#include <list>
#include <ranges>
#include <set>
#include <valarray>
#include <vector>

template<typename T> concept RAR = std::ranges::random_access_range<T>;

int main()
{
    int a[4];
    static_assert(
            RAR<std::vector<int>> and
            RAR<std::vector<bool>> and
            RAR<std::deque<int>> and
            RAR<std::valarray<int>> and
            RAR<decltype(a)> and
        not RAR<std::list<int>> and
        not RAR<std::set<int>> and
            RAR<std::array<std::list<int>,42>>
    );
}

Not me staring at these static_asserts like they’re the vibe check 😭 RAR is literally the whole concept in one tiny alias, and the example runs it against all those containers. Iconic.

🎀 See also 🎀

• ranges::sized_range — specifies that a range knows its size in constant time — (C++20) (concept)
• ranges::contiguous_range — specifies a range whose iterator type satisfies contiguous_iterator — (C++20) (concept)

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mwah 💋 source: http://cppreference.com • version/date: 2024.06.10 • page: std::ranges...ccess_range(3) — periodt, bestie 🌈✨