Inheritance in Kotlin

// Open class (can be inherited)
open class Animal(val name: String) {
    open fun makeSound() {
        println("Some generic animal sound")
    }

    fun sleep() {
        println("$name is sleeping")
    }
}

// Inheritance
class Dog(name: String, val breed: String) : Animal(name) {
    override fun makeSound() {
        println("$name barks: Woof!")
    }

    fun wagTail() {
        println("$name is wagging tail")
    }
}

// Abstract classes
abstract class Shape {
    abstract val area: Double
    abstract fun draw()

    fun describe() {
        println("Area: $area")
    }
}

class Circle(private val radius: Double) : Shape() {
    override val area = Math.PI * radius * radius

    override fun draw() {
        println("Drawing circle with radius $radius")
    }
}