Question

Say I got:

class X_
{
public:
    void do() { }
}

class Y_ : public X_
{
}

And I have this function:

void foo(X_ whatever)
{
  whatever.do();
}

Can I send a “Y_” object to the foo function, would this work?

I just realized that I could have tested this myself 🙂

Answer 1

Yes, but it will get sliced – all the Y_ parts of the object will be chopped off, and it will become an X_. You normally need to pass by reference in this situation, as normally do() will be a virtual function:

void foo(X_ & whatever)   // ampersand means whatever is a reference
{
  whatever.do();
}

BTW, I don’t know what you think those suffixed underscores are gaining you, but I would have said “nothing”.