The second Kotlin program

fun main () {
    var k: Boolean = true
    when(k) {
        true -> println("true")
        false -> println("false")
        else -> println("error")
    }

    /*var a: Int = 4
    when(a) {
        1,2,3 -> println("a in 1..3")
        4,5,6,7,8 -> println("a in 4..8")
        9,10 -> println("a in 9..10")
        else -> println("Wrong Answer!")
    }

    a = 88
    when(a) {
        in 91..100 -> println("A")
        in 81..90 -> println("B")
        in 71..80 -> println("C")
        in 61..80 -> println("D")
        in 0..60 -> println("E")
        else -> println("Wrong Answer!")

    a = 3.14
    when(a) {
        is Int -> println("The type of the value is \"Int\"")
        is Double -> println("The type of the value is \"Double\"")
        else -> println("Wrong Answer!")
    }*/

    println(sum(2, 3))
    //println(sum(b = 2, 3))    b参数此时为具名实参
}

fun sum(a:Int, b:Int):String {    //Kotlin形参都是常量
     return "The answer is " + (a + b)
 }
//fun sum(a:Int, b:Int): Int = a + b
//fun sum(a:Int, b:Int) = a + b

fun printer(name:String = "You haven't entered anything."): String{
    return "Welcome to the world of Kotlin $name"
 }