data class Human(var width: Int, var weight: Int, var name: String)

fun main(args: Array<String>) {
    fun sum(a: Int, b: Int): Int = if(a > b) a else b

    fun getStringLength(obj: Any): Int? {
        if (obj !is String) return null
        return obj.length
    }

    val arrayList = ArrayList<String>()
    for (s in arrayList) {
        println("string : $s")
    }


    cases("Hello") // String
    cases(2) // Int
    cases(System.currentTimeMillis()) // Long
    cases("hello") // Unknown

    for(x in 1..5) {
        println(x)
    }


    val array1 = ArrayList<String>()
    array1.add("aaa")
    array1.add("bbb")
    val ar1 = 5
    if (ar1 !in 0..array1.size - 1) println("Out: array 사이즈는 ${array1.size} 요청한 x = $ar1")

    val human: Human = Human(23,45,"정지훈")

    println(human.name)

    println(test())

    val mapTest = mapOf("a" to "HI", "b" to "FYCJ")

    for((K, V) in mapTest) {
        println("$K -> $V")
    }

    val toa: Long =  4241241;
    val tob: Int = toa.toInt();

    println(ClassName.getInstance())

}

fun test(obj: Any = "default"): Any? {
    return obj;
}

fun cases(obj: Any) {
    when(obj) {
        1 -> println("One")
        "Hello" -> println("Greeting")
        is Long -> println("Long")
        !is String -> println("Not a string")
        else -> println("Unknown")
    }
}

open class Base(age: Int)

class UseBase(age: Int): Base(age)

class ClassName private constructor() {
    companion object {
        fun getInstance() = ClassName()
    }
}

class Sample2 constructor(val name: String) {
    constructor(name: String, age: Int): this(name)
    constructor(name: String, age: Int, birthday: String): this(name, age)
}