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CSE205 Lecture 07a

CSE205 Lecture 07a

Object-Oriented Programming and Data Structures
Polymorphism
(202109)

Javier Gonzalez-Sanchez
PRO

September 17, 2021
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  1. jgs CSE 205 Object-Oriented Programming and Data Structures Lecture 07:

    Inheritance II Dr. Javier Gonzalez-Sanchez javiergs@asu.edu javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment
  2. jgs Previously…

  3. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 3 jgs

    Inheritance § Constructors are not inherited § A child’s constructor is responsible for calling its parent’s constructor. § Keyword: super
  4. jgs Test Yourselves super

  5. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 5 jgs

    Case 1 # name:String + Vehicle() + Car()
  6. jgs Javier Gonzalez-Sanchez | SER332 | Spring 2018 | 6

    class Car extends Vehicle{ public Car(String n) { super (n); } } class Vehicle { protected String name; public Vehicle(String n) { name = n; } } Case 1
  7. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 7 jgs

    Person
  8. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 8 jgs

    Student and Professor
  9. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 9 jgs

    Main What is the output?
  10. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 10 jgs

    Main
  11. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 11 jgs

    Case 2: Make this work
  12. jgs Inheritance Override and Overload

  13. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 13 jgs

    Method Overriding § A child class can override (redefine) the definition of an inherited method. (The new method must have the same signature.) § A method with the final modifier cannot be overridden. Warning: § Applied to variables final modifier makes them constant.
  14. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 14 jgs

    final
  15. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 15 jgs

    final
  16. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 16 jgs

    Method Overloading § The process of using the same name for multiple methods with different number or type of the parameters 16
  17. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 17 jgs

    Method Overloading public int calculate (int num1, int num2) { int sum = num1 + num2; return sum; } public int calculate (int num1, int num2, int num3) { int sum = num1 + num2 + num3; return sum; } 17
  18. jgs Inheritance Abstract Classes and Interfaces

  19. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 19 jgs

    We do not want to allow this
  20. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 20 jgs

    Abstract Classes § cannot be instantiated and contains one or more abstract methods (no definition body). § can contain methods § can contain data declarations
  21. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 21 jgs

    Abstract Classes
  22. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 22 jgs

    Abstract Classes
  23. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 23 jgs

    Abstract Methods § An abstract method is a method without a body. § It cannot be final or static because there is no definition, and it should be changed later.
  24. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 24 jgs

    Abstract Methods
  25. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 25 jgs

    Abstract Methods
  26. Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 26 jgs

    Questions
  27. jgs CSE 205 Object-Oriented Programming and Data Structures Javier Gonzalez-Sanchez,

    Ph.D. javiergs@asu.edu Fall 2021 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.