Chapter 12

Question 1

What must any OOP language support?

Answer 1

ADT
Inheritance
Polymorphism

Question 2

Why is Inheritance needed?

Answer 2

Can increase productivity (reuse)

Question 3

What are some OO concepts?

Answer 3

ADT (classes)
class instances (objects)
class that inherits (derived/subclass)
parent class
subprograms defining operations on objects (methods)
Calls to methods (messages)
collection of an object’s methods (message protocol/interface)
2 parts in message (method name, dest object)

Question 4

What are the 2 kinds of variables in a class?

Answer 4

Class variables (one per class)
Instance variables (one per object)
same for methods

Question 5

What is Dynamic binding?

Answer 5

Polymorphic reference (pointer)

Question 6

When everything is an object what are the advantages and disadv?

Answer 6

Adv: elegance
Disadv: slow

Question 7

When you add objects to a complete typing system what happens?

Answer 7

Speed up simple operations
Results in confusing type system

Question 8

When using an imperative typing system for primitives and make everything else object what happens?

Answer 8

Simple operations can be fast but typing system remains small
but 2 type systems has to mix

Question 9

What does dynamic binding look like in C++?

Answer 9

virtual key word, interface in java