CSE205 Lecture 06

Object-Oriented Programming and Data Structures
Inheritance I
(202202)

Transcript

1. jgs CSE 205 Object-Oriented Programming and Data Structures Lecture 06: Inheritance I Dr. Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment
2. jgs Inheritance
3. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 3 jgs Inheritance § Instead of repeating similar data/method definitions in several classes, we can define one class with the common instance data/methods, and let other classes inherit (extend) these data/method definitions. § Java: parent (super) class and child (sub) class § C++: base class and derived class § New class inherits existing members (variables and functions), add members, and redefine members
4. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 4 jgs Single Inheritance § Java supports single inheritance only, i.e., A child class can have only one parent class (direct parent, not ancestors)
5. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 5 jgs Classes
6. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 6 jgs Classes are Better with a Family
7. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 7 jgs Classes are Better with a Family
8. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 8 jgs Classes are Better with a Family
9. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 9 jgs Protected § Child classes do not inherit private variables § Protected variables and methods can be inherited by child classes, but not as accessible as public § If you plan to have a class inherited by other classes, its data should be declared as protected
10. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 10 jgs Protected
11. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 11 jgs Classes are Better with a Family
12. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 12 jgs Classes are Better with a Family (UML)
13. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 13 jgs Note In the Class Diagram: § Parameters are optional § Inherited members are implicit, just like with the source code
14. jgs Inheritance Constructors
15. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 15 jgs Inheritance § Constructors are not inherited § A child’s constructor is responsible for calling its parent’s constructor. § Keyword: super
16. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 16 jgs Person
17. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 17 jgs Student and Professor
18. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 18 jgs Main What is the output?
19. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 19 jgs Main
20. jgs To be Continued…
21. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 21 jgs Questions
22. jgs CSE 205 Object-Oriented Programming and Data Structures Javier Gonzalez-Sanchez, Ph.D. javiergs@asu.edu Spring 2022 Copyright. These slides can only be used as study material for the class CSE205 at Arizona State University. They cannot be distributed or used for another purpose.