Inheritance

Inherently good for you.

For today

• Why?
• What?
• How?

Why Inheritance?

class Student
    introduce()
    getName()
    getBirthday()
    getGpa()
    

class Professor
    introduce()
    getName()
    getBirthday()
    getClassName()    

INHERITANCE

What is Inheritance?

Our case

Student

Professor

?

Inheritance:

Inheriting a parent class' fields and methods

With Inheritance, we can:

• Declare new fields
• Declare new methods
• Override parent methods with a custom implementation

How do we use inheritance?

In Java

public class Professor extends Person {
}

keyword: extends

public class Person {
    public String name;
    public String birthday;

    public Person() { ... }
    public String getName() { ... }
    public String getBirthday() { ... }
    public String introduce() { ... }
}

public class Professor extends Person {
    public String className;
    
    public Professor() { ... }
    public String getClassName() { ... }
}

public class Student extends Person {
    public float gpa;
 
    public Student() { ... }   
    public float getGPA() { ... }
}

public static void main(String[] args) {
    ....

    Student student = new Student("Charles", "4/11/1995", 3.4);
    System.out.println(student.introduce());
}

Where is introduce()?

Student -> Person

public class Professor extends Person {
    public String className;
    
    public Professor() { ... }
    public String getClassName() { ... }
    public String introduce() { ... }
}

In Action

super()

Next Time:

It's super() important.