1. Object Oriented Programming: Inheritance
Chapter 9

2. Introduction Software Reusability Write programs in __________ fashion
saves __________ in program development
encourages use of proven, debugged code
______________ problems
Write programs in __________ fashion
Enables software designers to deal with complexity of modern software

3. Introduction When creating a new class …
designate that class to __________ data members, functions of previously defined superclass
result is a _______________
Subclass adds new __________ and ____________
Replace and refine existing members

4. Base Classes & Derived Classes
Superclass is more _______________
student, shape, loan
______________ is more specific
grad student, undergrad
circle, triangle, rectangle
carloan, home improvement, mortgage
Some languages talk of
____________ class (Superclass)
Derived class (Subclass)

5. Superclass and Subclass
Inheritance produces _________ like structures
Banking Hierarchy
Super-Now Account
Derived Class
Checking Account
Savings Account
Bank Account
Base Class
- Checking & Savings are derived from Bank Account Class
- Super-Now class derived from Checking class

6. Design Tip Important link between subclass and superclass Examples
The “______________” relationship
Examples
A checking account IS-A banking account
A savings account IS NOT a checking account
If there is no IS-A relationship, do not use ______________

7. Declaring Classes Using Inheritance
View superclass Point.java, Figure 9.9
View subclass Circle.java, Figure 9.10
Note
The _____________ specification for the superclass data
The ____________ specification
The implicit call to the superclass constructor
The explicit call with super( … )
View the test program, Figure 9.11

8. Comments on Private vs. Protected
Use protected when
Superclass should ___________________ only to its subclasses
Should not provide service to __________
Use private so that
Superclass ______________ can change without affecting subclass implementations
Author advocates _____________ protected
Instead provide set and get methods to access private data items (see Figures 9.12, 9.13 in text)

9. Three Level Inheritance Hierarchy
So far we have superclass Point and subclass Circle
Consider creating a subclass Cylinder, derived from Circle
View class Cylinder, Figure 9.15
Note the program for testing class Cylinder, Figure 9.16

10. Constructors in Subclasses
When you instantiate a subclass object
Subclass constructor invokes ____________ constructor
Implicitly
Explicitly with _____________ reference
____________ constructor performs its own tasks
Superclass constructor may also invoke a ___________ in the next class up the hierarchy
Last constructor in the chain is always the constructor for ______________

11. Finalizers in Subclasses
When classes in your hierarchy declare their own finalize methods …
A _____________ finalize should invoke the superclass finalize as its ____________
Ensures all parts of an object are finalized properly
Marked correctly for __________________
Note example of finalize functions in Figures 17, 18, and the test Figure 9.19

12. Software Engineering with Inheritance
At the design stage, certain classes found to be closely related
Factor out ____________ attributes, behaviors
Place these in a ________________
Use _______________ to develop subclasses with inherited capabilities
This avoids proliferation of classes, "reinventing the wheel"
Note
Declaring a subclass does not affect superclass ___________________