Pure virtual methods cannot be inherit?

[Rafael Justo]

Check the following code example:

///////////////////////

class A
{
public:
  int a;
};

///////////////////////

class B : public A {};

///////////////////////

class C
{
public:
  virtual void c(A *a) = 0;
};

///////////////////////

class D : public C
{
  void c(B *b) {}
};

///////////////////////

int main()
{
  D d;
  return 0;
}

The compiler gives me the following error:
cannot declare variable ‘d’ to be of abstract type ‘D’ because the following virtual functions are pure within ‘D’: virtual void C::c(A*)

I don't understand why the compiler doesn't accept it. The object used in the parameter is an extension of the original one used in the abstract class.

Any ideas?

Best regards,
Rafael

[newb16]

They can be inherited, but the argument list must be the same - the fact that B is inherited from A doesn't matter.