Variables in kotlin

 package com.example.my_kotlin_practice

fun main(args: Array<String>)
{
    var name = "Helle World"
    var age = 22
    var height = 8

    println(name)
    println(age)
    println(height)

    // variable values using $ sign
    println("Name : $name")
    println("Age : $age")
    println("Height : $height")

    // variable values without using $ sign
    println("Name : " + name)
    println("Age : " + age)
    println("Height : " + height)

    // Mutable variables
    name = "How are you ?"
    age = 24
    println("Name : $name")
    println("Age : $age")

    // Read-only variables
    /* A read-only variable can be declared using val (instead of var) and once a value is assigned,
    * it can not be re-assigned */
    val bat : String = "Tomorrow"
    val toy : Int = 20

    println("Bat : $bat")
    println("Toy : $toy")

    //bat = "Hello brother"   //Not allowed, throws an exception
    //toy = 22                //Not allowed, throws an exception

    //Variables types
    var name2 : String = "Today"
    var age2 : Int = 45

    println("Name2 : $name2")
    println("Age2 : $age2")

//    Kotlin variable names can contain letters, digits, underscores, and dollar signs.
//    Kotlin variable names should start with a letter or underscores
//    Kotlin variables are case-sensitive which means Zara and ZARA are two different variables.
//    Kotlin variable can not have any white space or other control characters.
//    Kotlin variable can not have names like var, val, String, Int because they are reserved keywords in Kotlin.
}

OUTPUT :

Helle World
22
8
Name : Helle World
Age : 22
Height : 8
Name : Helle World
Age : 22
Height : 8
Name : How are you ?
Age : 24
Bat : Tomorrow
Toy : 20
Name2 : Today
Age2 : 45

Process finished with exit code 0