Kotlin Android programming Language basics

Kotlin Programming Introduction

1. Introduction to Kotlin programming Language:

   Google announced Kotlin as officially supported language for Android.

   Kotlin is a great fit for developing server-side applications, allowing to write concise and expressive code

   Kotlin provides ability to target javascript

   Kotlin is a statically typed programming language that runs on Java virtual machine(JVM) and also can be compiled to Javascript source code.
   Google I/O 2017 it was declared as one of the official programming languages to develop Android applications along with Java and C++.

2. “Hello World” program in Kotlin
   visit http://kotlinlang.org/ and TRYONLINE will help you write some sample programs online.

//save the file as hello.kt
package demo   //package is optional
fun main(args:Array<strings){   
/*fun keyword shows its a function and args is argument  of type array of strings*/
println(“hello world”)
}

3.From command line you can compile hello.kt using below command

                   The -d option indicates what we want the output of the compiler to be called and may be either a directory name for class files or a .jar file name. The -include-runtime option makes the resulting .jar file self-contained and runnable by including the Kotlin runtime library in it.
                   Run the application.
$java -jar hello.jar

4.Basic data types in Kotlin are :
Double = 64bit,Float=32bit,Long=64bit,Int=32bit,Short = 16bit,Byte=8bit

Variable declaration and Initialization:
'val a: Int = 100'

Char type

'val b:Char = 'b''

Array type

Arrays in Kotlin are represented by the Array class, that has get and set functions

Method1:
val arr = arrayOf(1,2,3)
Method2:

  val arr:IntArray = intArrayOf(1,2,3)
  val x:CharArray = charArrayOf('a','b','c')

String Datatype:
Strings are represented by the type String.
Strings are immutable

    `val str = "hello world"`

6.Difference between val and var
val variables are immutable
var variables are mutable, means can be reassigned