#include <array>
#include <iostream>
#include <span>

int main() {
    std::array<int, 3> values{2, 4, 6};
    std::span<int> view{values};
    std::span<const int> read{values};
    std::cout << view.size() << ' ' << view[1] << '\n';

    const std::span<int> fixed{view};
    fixed[1] = 7;
    std::cout << read[1] << '\n';

    const std::span<const int> empty{};
    std::cout << empty.size() << ' ' << empty.empty() << '\n';
    return 0;
}