#include <iostream>
#include <tuple>
#include <vector>
#include <experimental/optional>

template<class ...Cs>
class Container
{
public:
	template<class T> using Optional = std::experimental::optional<T>;

	std::vector<std::tuple<Optional<Cs>...>> elements;
	
	template<class C>
	C get(std::size_t index) const
	{
		return optional<C>(index).value();
	}
	
	template<class C>
	C get(std::size_t index, C&& defaultValue) const
	{
		return optional<C>(index).value_or(std::move(defaultValue));
	}
	
	template<class C>
	void set(std::size_t index, const C& c)
	{
		optional<C>(index) = c;
	}
	
	template<class C, class... Args>
	void emplace(std::size_t index, Args&&... args)
	{
		optional<C>(index).emplace(args...);
	}
	
	template<class C>
	bool has(std::size_t index) const
	{
		return optional<C>(index);
	}

protected:
	template<class C>
	const Optional<C>& optional(std::size_t index) const
	{
		return std::get<Optional<C>>(elements.at(index));
	}

	template<class C>
	Optional<C>& optional(std::size_t index)
	{
		return std::get<Optional<C>>(elements.at(index));
	}
};

int main()
{
	Container<int, double> container;
	container.elements.resize(10);
	container.emplace<int>(0, 69);
	std::cout << container.get<int>(0) << std::endl;
	return 0;
}