Question

Is it possible to return a template?

This is what I’ve been trying, but this isn’t working.

template<int degree>
class Polynomial
{
public:

   ... ususal stuff ...

   // Polynimal<degree - 1>
   Polynomial derivative() { /* returns a different template */ }

};


int main()
{
   Polynomial<3> cubic;
   Polynomial<2> parabola;

   parabola = cubic.derivative();
}

Is this possible? What little nugget am I missing?

Answer 1

You can make the member-function a function template:

template<int ret_degree>
Polynomial<ret_degree> derivative() { /* returns a different template */ }

Or, if you know the degree of the return-polynomial, you can do something like this:

Polynomial<degree-1> derivative() { /* returns a different template */ }