// constants
val one = 1 // Int
val threeBillion = 3000000000 // Long
val oneLong = 1L // Long
val oneByte: Byte = 1
 
// variables
var a: Byte = 0  	// signed 1 byte
var b: Short = 0	// signed 2 bytes
var c: Int = 0		// signed 4 bytes
var d: Long = 0 	// signed 8 bytes
 
var ff: Float = 0f		// 32 bit floating
var fd: Double = 0.0	// 64 bit floating
 
 
/*
 * All number types support conversions to other types:
      toByte(): Byte
      toShort(): Short
      toInt(): Int
      toLong(): Long
      toFloat(): Float
      toDouble(): Double
      toChar(): Char
*/
 
val myTrue: Boolean = true
val myFalse: Boolean = false
val boolNull: Boolean? = null
 
val str = "abcd 123"
 
class Ref(val a: Int, val b: Int) {
 
	val customerKey = a.toString().uppercase()
 
 
     val area: String
        get() = a.toString() + "+" + b.toString() + "=" + (a + b).toString()
 
     private var customA: Int = 0;
   	 var refA: Int
    	get() = customA
        set(value) {
            customA = if (value > 0) value else 0
        }
 
}
 
 
fun demo(x: Any) {
    if (x is String) {
        print(x.length) // x is automatically cast to String
    }
}
 
 
fun main() {
    val asc = Array(5) { i -> (i * i).toString() }
	asc.forEach { println(it) }
 
    val name: String = "world";
    val r = Ref(3, 17);
    println("Hello, ${name}!!!")
    println(r.area)
}