Difference between abstract and virtual?

Question

As far as I can tell, they seem to be doing the same thing.

david 0 · Answer

No, you will HIDE it... class Base { void f(); virtual void g(); } class Derived : Base { new void f(); override void g(); } void main() { Derived d = new Derived(); d.f() // Call Derived.f(); d.g() // Call Derived.g(); Base b = d; b.f() // calls Base.f(); b.g() // calls Derived.g();

Amit Mishra · Answer

But even if a method is not virtual I can still override it in the subclass right? Thanks.

david 0 · Answer

Actually for C#, an abstract class can have code in it, but the abstract method can not. This is different from C++ where a method can be marked as "pure virtual" (which REQUIRES it to be overriden), but still has a body (implementation).

bonnieb · Answer

Oooops, my bad ... I got an abstract class mixed up with an interface. Sorry ... an abstract class *can* have code in it, but you can only use the class for sub-classing other classes. In other words, it can't be instantiated itself. ~~Bonnie

bonnieb · Answer

No, they're not the same. No code at all goes into an abstract class, just things like method names, etc. A class based on an abstract class will need to have code in all the methods. A virtual method however, can have code in it, which you can, if you wish, override in the subclass. ~~Bonnie

Difference between abstract and virtual?

Answers (5)