std::ranges...iguous_range(3)

💖 NAME 💖

okay bestie, welcome to the std::ranges::contiguous_range(3) page from the C++ Standard Library 💅 this one is niche but iconic, iykyk.

std::ranges::contiguous_range — yes queen, that's the name, and that's also literally the concept. No cap.

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🌸 Synopsis 🌸

📍 Defined in header <ranges>

⏱️ Since C++20, periodt.

template< class T >
  concept contiguous_range =
    ranges::random_access_range<T> &&
    std::contiguous_iterator<ranges::iterator_t<T>> &&
    requires(T& t) {
      { ranges::data(t) } ->
        std::same_as<std::add_pointer_t<ranges::range_reference_t<T>>>;
    };

so the contiguous_range concept is a refinement of range — the way that ranges::begin returns a model of contiguous_iterator, and the customization point ranges::data is usable. that's the whole vibe check 💫

💫 Semantic requirements 💫

T models contiguous_range only if, given an expression e such that decltype((e)) is T&, this holds:

std::to_address(ranges::begin(e)) == ranges::data(e)

periodt, that's the requirement. no extra lore, no secret handshake 🫶

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✨ Example ✨

// Run this code — bestie, run it, it's giving compile-time main character energy 😭

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

template<typename T> concept CR = std::ranges::contiguous_range<T>;

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

the static_assert ate that whole lineup, lowkey obsessed 💅✨

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🦋 See also 🦋

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

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source/version: http://cppreference.com · date: 2024.06.10 — bye bestie, go be contiguous and iconic 💖✨🎀