What's the difference between virtual function instantiations in C++?

Question

What\'s the difference between the following two declarations?

virtual void calculateBase() = 0;  
virtual void calculateBase();

I read the fir

Answer 1

In Java

virtual void calculateBase() = 0;  

would be

abstract void calculateBase();

and

virtual void calculateBase();

would be

void calculateBase();

To be perfectly clear,

void calculateBase();

in C++, is "the same" as

final void calculateBase();

in Java. That is, final is "default" in C++. There is an exception to this rule however. When subclassing a class with a virtual method and reimplementing it without using the virtual keyword, the method in the subclass will not be final.

Answer 2

Basically, when inheriting, you are compelled to override the first one, and are allowed to override the second one.

Coming from Java, don't you?