Input

Standard input

Functions for handling standard input:

Function	Usage
`readln()`	Reads a line from stdin and returns it, or throws a `RuntimeException` if EOF has been reached.
`readlnOrNull()`	Reads a line from stdin and returns it, or returns `null` if EOF has been reached.

println("What is your nickname?")
val nickname = readln()
println("Hello, $nickname!")

var sum = 0
while (true) {
    val nextLine = readlnOrNull().takeUnless {
        it.isNullOrEmpty()
    } ?: break
    sum += nextLine.toInt()
}
println(sum)