Quiz

1.	What is abstraction?
2.	When should abstraction be used in a program?
3.	What is an abstract method?
4.	Can an abstract method be called within a program?
5.	What happens if an abstract method is not redefined?
6.	Can an instance of an abstract class be declared in a program?
7.	Can an abstract method be called directly by a subclass?
8.	Must an abstract method be redefined by a subclass?
9.	Must all methods in an abstract class be designated as abstract?
10.	Must all methods in an abstract class be redefined in a subclass?

Answers

1.	Abstraction is a way for the programmer of a super class to require the programmer of a subclass to define a method.
2.	Abstraction should be used in a program when there isn t any way to define a good default method in the super class.
3.	An abstract method is a method defined in a super class that must be redefined in a subclass that inherits the super class.
4.	An abstract method cannot be called within a program.
5.	A compiler error occurs if an abstract method is not redefined.
6.	An instance of an abstract class cannot be declared in a program.
7.	An abstract method cannot be called directly by a subclass.
8.	A programmer of a subclass that inherits an abstract super class must redefine the abstract methods defined in the subclass, even if those methods are not called within the application.
9.	A super class can contain a mixture of abstract methods and non-abstract methods.
10.	Only abstract methods must be redefined in a subclass that inherits from the abstract super class.