指向继承的类的指针

Question

Suppose we have a BaseClass Character and three SubClasses Good, Bad, Zombie. Also assume we have two pointers

Character* ptr1,ptr2;

that point in class Good,Bad or Zombie. I want to create a part of code like this:

if ((ptr1 "shows" Good)&&(ptr2 "shows" Bad)) {...} else if ((ptr1 "shows" Good)&&(ptr2 "shows" Zombie)) {...} else if ...

and so on. How can I write such a statement? I have a hard time understanding virtual functions, polymorphism and inheritance but feel free to explain in terms of those too.

Thank you, in advance.

Answer 1

You could declare a virtual public method in Character that returns an enum class representing the type of character, for example

virtual CharacterType GetCharacterType();
....
if((ptr1->GetCharacterType() == CharacterType::Good) && ptr2->GetCharacterType() == CharacterType::Bad)) {...}

or a virtual method that confirms the type of character.

virtual bool Is(CharacterType characterType);
....
if((ptr1->Is(CharacterType::Good) && ptr2->Is(CharacterType::Bad)) {...}

Answer 2

You could use dynamic_cast in the following manner:

if (dynamic_cast<Good*>(ptr1) && dynamic_cast<Bad*>(ptr2)) {
  ...
} else if (dynamic_cast<Good*>(ptr1) && dynamic_cast<Zombie*>(ptr2)) {
  ...
} else if ...