Book Image

Kotlin Quick Start Guide

By : Marko Devcic
Book Image

Kotlin Quick Start Guide

By: Marko Devcic

Overview of this book

Kotlin is a general purpose, object-oriented language that primarily targets the JVM and Android. Intended as a better alternative to Java, its main goals are high interoperability with Java and increased developer productivity. Kotlin is still a new language and this book will help you to learn the core Kotlin features and get you ready for developing applications with Kotlin. This book covers Kotlin features in detail and explains them with practical code examples.You will learn how to set up the environment and take your frst steps with Kotlin and its syntax. We will cover the basics of the language, including functions, variables, and basic data types. With the basics covered, the next chapters show how functions are first-class citizens in Kotlin and deal with the object-oriented side of Kotlin. You will move on to more advanced features of Kotlin. You will explore Kotlin's Standard Library and learn how to work with the Collections API. The book finishes by putting Kotlin in to practice, showing how to build a desktop app. By the end of this book, you will be confident enough to use Kotlin for your next project.
Table of Contents (15 chapters)
Title Page
Copyright and Credits
Dedication
Packt Upsell
Contributors
Preface
Index

Control flow


Kotlin has statements for determining what sections of the code will be executed next, during the runtime of a program. These statements are known as control flow statements. 

These statments are:

  1. If-else
  2. When
  3. Loops
  4. for loops
  5. while loops
  6. do-while loops

if-else

Kotlin’s if-else statements are expressions, not keywords. Which means they can have a value. Consider this example where an if-else expression is used to initialize a variable:

val str: String = if (num < 10) "Lower than 10" else "Equal or greater than 10"

When

Kotlin doesn’t have switch statements, like Java and other popular languages. Switch in other languages is a conditional operator which can be used for comparing multiple conditions on a variable.

In Kotlin this operator is called when and does the same job as a switch in other languages.

It checks the variable value against multiple conditions, and, if a condition is satisfied, it executes the expression for that branch. when is a lot more powerful than Java’s switch operator...