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jgs CSE 205 Object-Oriented Programming and Data Structures Lecture 07: Inheritance II Dr. Javier Gonzalez-Sanchez [email protected] javiergs.engineering.asu.edu | javiergs.com PERALTA 230U Office Hours: By appointment

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jgs Previously…

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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

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jgs Test Yourselves super

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 5 jgs Case 1 # name:String + Vehicle() + Car()

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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

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 7 jgs Person

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 8 jgs Student and Professor

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 9 jgs Main What is the output?

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 10 jgs Main

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 11 jgs Case 2: Make this work

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jgs Inheritance Override and Overload

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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.

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 14 jgs final

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

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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

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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

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jgs Inheritance Abstract Classes and Interfaces

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 19 jgs We do not want to allow this

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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

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 21 jgs Abstract Classes

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

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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.

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 24 jgs Abstract Methods

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

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Javier Gonzalez-Sanchez | CSE205 | Fall 2021 | 26 jgs Questions

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jgs CSE 205 Object-Oriented Programming and Data Structures Javier Gonzalez-Sanchez, Ph.D. [email protected] 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.