Hands-On Object-Oriented Programming with Kotlin

Type annotation

In Kotlin, we can also declare a specific type of variable with var variableName : nameOfDataType type annotation:

var myInteger : Intvar myString : Stringval myDouble : Double

Once the variables are declared, we can assign values to them:

myInteger = 10myString = "Hello"myDouble = 12.123

Having variable declarations with explicit data types and assigning a value at the same time is also possible:

val myInt : Int = 10var myString : String = "Hello"

Variable declaration and initialization is explained in the following example:

fun main(args: Array<String>) {    var myName: String // Variables can be initialized explicitly    myName = "Jon" // Initialization    // declaration and initialization in one line    var myInt: Int = 10 var myLong: ...