Virtual functions and polymorphism

Question

Suppose I have this:

class A
{
    public:
    virtual int hello(A a);
};

class B : public A
{
   public:
   int hello(B b){ bla bla };
};

So,

Answer 1

First, A is not an abstract class in your code. It must have at least one pure virtual function to be abstract.

1. different parameters means completely different method, even though the name is the same. Think of it as a different name. That's why it's called "signature". If A would be an abstract class, this code would not compile at all.

2. A::hello() will be called. No problem with that, and parameter must be type A, as if there was no inheritance.