C++的virtual和Java的abstract

Use to override functions in parent class.

(C++)virtual與pure virtual
Good summary table from the link above. There are good examples there also.

Virtual function: Differences between C++ and Java

	C++	Java
Pure Virtual Function	vitual void func() = 0;	abstarct void func();
Impure Virtual Function	vitual void func();	void func();
Non-Virtual Function	void func();	final void func();
Hiding Inherited Names	Yes	No
Prohibiting Inheritance	No	final class