functions with an indefinite number of parameters

I want realize code like this:

template <typename... Args>
class A
{
public:
    A(Args... args) {ind = std::make_tuple(args...);}
    std::tuple<Args...> ind;
};

void foo()
{
    std::cout << std::endl;
}

template <typename First, typename... Rest>
void foo(First _first, Rest... _rest)
{
    std::cout << _first;
    foo(_rest...);
}


int main()
{
    A<int, int> a1(1, 2);
    A<int, int, int> a2(1, 2, 3);
    A<int, int, int, int> a3(1, 2, 3, 4);

    foo(a1.ind);
    foo(a2.ind);
    foo(a3.ind);
}

In Class A the field ind does not have to be tuple, the main thing is that the function is passed pack of parameters.