readln

Reads a line of input from the standard input stream and returns it, or throws a RuntimeException if EOF has already been reached when readln is called.

expect fun readln(): String(source)
fun main() {
    println("What is your name?")
    val name = readln()

    println("How old are you?")
    val age = readln()

    println("Hello, $name! You are $age years old.")
}

Source