Question

Lets say I have a parent Class:

Class Parent{
public:
virtual void doSomething(){}
}

and two children:

Class Son: public Parent{
public:
  void doSomething(){
  // Do one thing
  }
}

Class Daughter: public Parent{
public:
  void doSomething(){
  // Do another thing
  }
}

If I setup an instance of a child class like this:

Parent obj = Son();

How do I properly invoke the doSomething() method that is defined by Son and not the empty function in Parent

Answer 1

In order to do this you need to make the Parent declaration a pointer or a reference.

Parent* obj = new Son();

In it’s current form your declaring obj to be an instance of Parent. This means the assignment from Son() doesn’t create a reference to a Son instance, instead it slices the object into a Parent value.

• http://en.wikipedia.org/wiki/Object_slicing