[변수 알아보기]

1. var, val

fun main(args: Array<String>) {

    var i: Int = 10
    val j: Int = 10

    i = 20
//    j = 20

    println(i)
    println(j)
}

 

2. null 허용

fun main(args: Array<String>) {

    var i: Int = 10
    var j: Int? = 10

//    i = null
    j = null

    println(i)
    println(j)
}

 

3. 타입추론

fun main(args: Array<String>) {

    val s = "ABC"
    val i = 1
    val l = 1L
    val d = 1.0
    val f = 1.0f

    println("s = " + s::class)
    println("i = " + i::class)
    println("l = " + l::class)
    println("d = " + d::class)
    println("f = " + f::class)
}