#include <iostream>
#include <ranges>
#include <vector>
#include <sstream>

template<class T, class A>
class VectorView : public std::ranges::view_interface<VectorView<T, A>>
{
public:
    VectorView() = default;

    VectorView(const std::vector<T, A>& vec) :
        m_begin(vec.cbegin()), m_end(vec.cend())
    {}

    auto begin() const { return m_begin; }

    auto end() const { return m_end; }

private:
    typename std::vector<T, A>::const_iterator m_begin{}, m_end{};
};

int main()
{
    std::vector<int> v = { 1, 4, 9, 16 };

    VectorView view1{ v };
    view1.size();
    view1.front();
    view1.empty();
    view1.back();
    view1.data();

    auto words = std::istringstream{ "today is yesterday’s tomorrow" };
    auto istream_view = std::views::istream<std::string>(words);;
    std::ranges::view_interface<std::ranges::basic_istream_view<std::basic_string<char, std::char_traits<char>, std::allocator<char> >, char, std::char_traits<char> > > view2 = istream_view;

    return 0;
}

<Intrinsic Optional="true" Name="size" Expression="(size_t)(_Bound - _Value)" />