C++ help/ Toy problem

Hi, I am trying to learn c++ and I am stuck on this toy problem. It is not a trick, there is a working solution in the given constraints, but it is a little tricky and unorthodox I think. The pointers, virtual tables, and public/private methods are really giving me a hard time.

Here is the problem:

Only writing code where indicated and without defining any new classes, try to get the program to output the following things (only one at a time, since there is only one return value):

Here is the code:

#include <cstdio>

class Thing
{
private:
      int x;
      int y;
      virtual int doStuff()
      {
            return x+y;
      }
      virtual int doStuff2()
      {
            return x*y;
      }
public:
      Thing(){
            x = 2;
            y = 10;
      }
};

int extractThing(void* thing)
{
      //insert code here
      //return the value to be printed
}

int main()
{
      Thing thing;
      printf("%d\n", extractThing(&thing));
      return 0;
}