I have three classes and I want to use each of them inside another
likeso:

```
class Object
{
public:
    Object();
    ~Object();

protected:

   int x;
   int y;
private:
  Line l;
  Circle c;
}; 

class Line : public Object
{
public:
    Line ()
        {
           x = x+y;
         }
    ~Line ();

private:
}; 

class Circle : public Object
{
public:
    Circle()
        {
           x = x/y;
         }
    ~Circle();

private:
}; 

```

So the problem here is that I get an error on compilation which says base undefined,
I have tried to use `#define` and `#ifdefine`, but it doesn't work.

Ideally, what I want to do is to have one object in `main` to call and all other variables to be used will be set there and at the same time this object could be different such that it could be a `Line` or `Circle`.