c++11 meta sequence

pack_array.hpp

template<typename T, T... _Rest>
struct array_pack;
template<typename T>
struct array_pack<T>{};
template<typename T, T _This, T... _Rest>
struct array_pack<T, _This, _Rest...> : private array_pack<T, _Rest...>
{
	const T & operator[](const int pos)
	{
		//as cpp memory layout, indexing reversely
		return ((T *)this)[sizeof...(_Rest)-pos];
	}
	constexpr int size() const
	{
		return sizeof...(_Rest)+1;
	}
private:
	T _this = _This;
};

//use like this
array_pack<int, 1, 10, 100, 1000> pack;
int sz = pack.size();
int a0 = pack[0];
int a1 = pack[1];
int a2 = pack[2];
int a3 = pack[3];