Hands-On Object-Oriented Programming with Kotlin

Using the open keyword

To open classes in Kotlin, we can add the open keyword at the beginning of the superclass signatures:

open class Person (val fName: String, var lName: String, var pAge: Int, val ID : String) {    fun speak() {        println("My name is $fName $lName, my id is $ID and age is $pAge")    }    fun greet() {        println("Hi How are you...")    }}class Student(fName: String, lName: String, pAge: Int, ID: String ): Person(fName,lName,pAge, ID) {    fun aboutEducation(){        println("I am a student of Computer Science.")    }    fun attendLectures() {        println("I am studying Introduction to Kotlin lecture.")    }}

Now, the Student child class has access to all the functions of the Person class, and has its own properties and functions as well. We will add two functions ...