Question regarding the output and use of a function combined with a structure in C++

Question

We are given the task to create horner's rule by making three separate functions combined with a structure. The structure looks like this:

struct Polynomial
{
    long n;
    double* a;
};

Next I created a function that is supposed to take in the polynomial degree and coefficient:

Polynomial createPoly()
{
    Polynomial poly;
    std::cout << "Enter polynomial degree: ";
    std::cin >> poly.n;

    poly.a = new double[poly.n];
    for (int i = 0; i < poly.n; i++)
    {
        std::cout << "The polynomial coeff x ^ " << i <<" = " << std::endl;
        std::cin >> poly.a[i];
    }

    return poly;
}

Note that everything except the code written after cin>>poly.n; is mandatory. My question now is, what is my createPoly function exactly? It has the structure definition before and takes no values as function inputs. How would I be able to use poly.n and poly.a in other functions?

For example, I now have to create a function which calculates the polynomial through horners rule but I have no clue on how I would be able to combine it with my createPoly function.

double calcPoly(double x, const Polynom* poly); //calc poly defintion

Thanks in advance.

Answer 1

Your function createPoly returns a Polynomial object so you could write something like:

Polynomial p = createPoly();
double result = calcPoly(1.56, &p);

Basically, the createPoly function returns an object that you can then set into a variable and use in your other functions like calcPoly or any others.