Inheritance in classes. C++

Question

Let's say I am creating a tree, and I have a class of Node and a class of Cars.

   class Cars : public Node{
     ....
    };

If I have an object all ready defined as a Node, but I now want it to make it a Car as well, how would I do it?

Thank you !

Answer 1

The closest thing you can do is to supply a conversion constructor for your Cars class and create a new instance:

class Node
{
    // stuff goes here
};

class Cars : public Node
{
public:
    // other constructors, destructor, members, etc.
    Cars(const Node& node)
    {
        // copy node data into the Node portion of the car
    }
};

int main()
{
    Node n;
    Car c(n);
    return 0;
}

If you create it as a Node first, you cannot magically change it to a Car without creating an actual Car instance and copying the data into it.