KOTLIN Tutorial

Introduction to Kotlin

Why Kotlin?

• Concise Syntax: Reduces boilerplate code, making the code cleaner and more readable.
• Null Safety: Built-in null safety to prevent NullPointerExceptions.
• Interoperability with Java: Works seamlessly with existing Java libraries and frameworks.
• Modern Features: Includes advanced features like extension functions, lambdas, and more.

Basic Kotlin Syntax

Here’s a simple Kotlin program that prints “Hello, Kotlin!” to the console:

// Simple Kotlin Program
fun main() {
    println("Hello, Kotlin!")
}

In Kotlin, functions are defined using the fun keyword, and the println() function outputs text to the console.

Variables in Kotlin

In Kotlin, there are two types of variables:

• val: Immutable (read-only) variables, meaning their value cannot be changed.
• var: Mutable variables, meaning their value can be modified.

Example: Declaring Variables

val name: String = "Kotlin"  // Immutable
var age: Int = 5             // Mutable

Functions in Kotlin

Functions are essential in Kotlin, and they are defined using the fun keyword:

fun greet(name: String) {
    println("Hello, $name!")
}

// Calling the function
greet("World")

The greet function takes a String parameter and prints a greeting message.

Null Safety in Kotlin

Kotlin has built-in null safety features to avoid NullPointerExceptions:

• Nullable types: Variables that can hold a null value are declared using ?. Example: var name: String? = null.
• Safe calls: The ?. operator allows safe access to a nullable variable. Example: name?.length.

Example: Null Safety

var name: String? = null

// Safe call operator
println(name?.length)  // Will print null, no exception thrown

Conclusion

Kotlin is a modern, concise, and powerful language that is ideal for a wide range of applications, from Android development to backend services. Its features such as null safety and full interoperability with Java make it a top choice for developers looking for a more efficient and expressive language.