How the pattern on a function template argument pack works?

Question

Hello I have this example about variadic function templates and patterns:

int& neg(int& x){ x = -x; return x;}

void f(int& x){
    std::cout << x << ", ";
}

template <typename T, typename...Args>
void f(T& x, Args&...args){
    f( neg(args)...);
}


int main(){

    int x = 1, y = 2, z = 3, a = 4;
    f(x, y, z, a);

    std::cout << x << ", " << y << ", " << z << ", " << a << '\n';

    cout << '\n';
}

The output:

-4, 1, -2, 3, -4

• I don't know why I get this output and why shouldn't it be -1, -2, -3 -4?

• Can someone explain to me what happens exactly when applying the pattern to the function argument pack: f(neg(args)...;? Thank you so much!

• It looks to me that it starts the pattern in reverse order I mean from the end to the beginning. isn't it?