#include <iostream>

template<class S>
S make_struct() {
    S s = {};
    return s;
}

template<class S, class T1>
S make_struct(T1 t1) {
    S s = { t1 };
    return s;
}

template<class S, class T1, class T2>
S make_struct(T1 t1, T2 t2) {
    S s = { t1, t2 };
    return s;
}

// ... etc.

struct X { int a, b; };

int main() {
    X x = make_struct<X>(1, 2);
    std::cout << x.a << ", " << x.b << "\n";
}