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

Operator overloading


Operator overloading is a mechanism where programming language operators are implemented in custom, user-defined types. Most of the operators in Kotlin are actually functions. If you define a function in your type named plus, then you can use the + operator with the instance of that type. This increases flexibility and allows you to have a type defined in Java, and then use operators instead of functions in Kotlin. Also, thanks to extension functions, this enables adding an operator to existing types that you don't own.

The following table shows how operators map to functions:

Operator

Function

a++

a.inc()

a--

a.dec()

a + b

a.plus(b)

a - b

a.minus(b)

a * b

a.times(b)

a / b

a.div(b)

a % b

a.rem(b)

a..b

a.rangeTo(b)

a in b

b.contains(a)

a[i]

a.get(i)

a[i] = b

a.set(i, b)

a += b

a.plusAssign(b)

a -= b

a.minusAssign(b)

a *= b

a.timesAssign(b)

a /= b

a.divAssign(b)

a %= b

a.remAssign(b)

a == b

a.equals(b)

a > b

a.compareTo(b) > 0

a < b

a.compareTo(b) < 0

a >= b

a.compareTo(b) >= 0

a <= b

a.compareTo...