Is an array in a member initializer list for a variadic struct possible?

Question

I created a variadic struct based on a std::tuple .

Then, I would like to use a C-style array in the member initializer list with automatic type deduction / class template argument deduction.

I created a minimum reproducible example:

#include <iostream>
#include <tuple>

template <typename ... Args>
struct VariadicStruct {
    std::tuple<Args...> data{};
    VariadicStruct() {}
    VariadicStruct(Args...args) {
        data = std::make_tuple(args...);
    };
    // More data and functions
    // . . .
};
int main() {
    VariadicStruct vs1{ {1,2,3}, 4.0, 'c' }; // Does not work
    std::cout << std::get<0>(vs1.data)[0] << '\t' << std::get<1>(vs1.data) << '\t' << std::get<2>(vs1.data) << '\n';

    VariadicStruct vs2{ 1, 4.0, 'c' };   // Fine
    std::cout << std::get<0>(vs2.data) << '\t' << std::get<1>(vs2.data) << '\t' << std::get<2>(vs2.data) << '\n';
}

I was hoping to create an array in the std::tuple using a nested braced initializer list. So, in the end, a std::tuple with int[3] , double and char types.

My guess: Automatic type deduction does not work here.

Is there any way to make this happen?

---

(This is not a duplicate of this )

Answer 1

With the very good comments from the community, I now implemented the code like the below:

#include <iostream>
#include <tuple>
#include <array>
#include <utility>

template <typename ... Args>
struct VariadicStruct {

    std::tuple<Args...> data{};

    VariadicStruct() {}
    VariadicStruct(Args...args) : data(std::forward<decltype(args)>(args)...)  {};

    // More data and functions
    // . . .
};
int main() {
    VariadicStruct vs1{ std::array{1,2,3}, 4.0, 'c' };
    std::cout << std::get<0>(vs1.data)[0] << '\t' << std::get<1>(vs1.data) << '\t' << std::get<2>(vs1.data) << '\n';
}