**Course Title:** Kotlin Programming: From Basics to Advanced Techniques **Section Title:** Advanced Functionality: Generics and Extension Functions **Topic:** Implement generics and extension functions in a Kotlin project.(Lab topic) **Lab Objective:** In this lab, you will apply your knowledge of generics and extension functions to create a Kotlin project. You will design and implement a system that utilizes both generics and extension functions to demonstrate your understanding of these advanced concepts. **Lab Overview:** In this lab, you will create a generic class called `Box` that can hold any type of object. The `Box` class will have methods to add, remove, and display the objects it holds. You will also create extension functions for the `Box` class to provide additional functionality. **Step 1: Create the Generic Box Class** Create a new Kotlin file called `Box.kt` in your project. Define a generic class `Box` with the following properties and methods: ```kotlin class Box<T> { private val elements: MutableList<T> = mutableListOf() fun add(element: T) { elements.add(element) } fun remove(element: T) { elements.remove(element) } fun displayElements() { println(elements.joinToString()) } } ``` **Step 2: Create Extension Functions for the Box Class** Create a new Kotlin file called `BoxExtensions.kt` in your project. Define two extension functions for the `Box` class: ```kotlin fun <T> Box<T>.isEmpty(): Boolean { return elements.isEmpty() } fun <T> Box<T>.contains(element: T): Boolean { return elements.contains(element) } ``` **Step 3: Test the Box Class and Extension Functions** Create a new Kotlin file called `Main.kt` in your project. Create a `Box` object and add some elements to it. Test the `displayElements`, `isEmpty`, and `contains` methods: ```kotlin fun main() { val box = Box<Int>() box.add(1) box.add(2) box.add(3) println(box.isEmpty()) // false println(box.contains(2)) // true box.displayElements() // 1, 2, 3 box.remove(2) box.displayElements() // 1, 3 } ``` **Key Concepts and Takeaways:** * Generics: You learned how to create a generic class that can hold any type of object. * Extension functions: You learned how to create extension functions for a class to provide additional functionality. * Type safety: You learned how to use generics to ensure type safety in your code. **Additional Resources:** * For more information on generics, see the [official Kotlin documentation](https://kotlinlang.org/docs/reference/generics.html). * For more information on extension functions, see the [official Kotlin documentation](https://kotlinlang.org/docs/reference/extensions.html). **Exercise:** * Create a generic `Pair` class that can hold two objects of any type. * Create extension functions for the `Pair` class to return the first and second elements. * Test the `Pair` class and extension functions. **Comments and Help:** If you have any questions or need help with this lab, please leave a comment below.