/*
 * File: another_prime.kt
 * Purpose: Reads a positive integer from user,
 *   and prints a message saying whether
 *   the number read in is prime or not.
 * Author: SS
 */
fun main(args: Array<String>) {
    // read in n
    print("Please type in a positive integer: ")
    val n = readLine()!!.toInt()

    // check whether n is prime
    var isPrime = when {
        n == 1 -> false
        n == 2 -> true
        n % 2 == 0 -> false
        else -> {
            var hasNonTrivialDivisor = false
            var d = 3
            while (d * d <= n) {
                if (n % d == 0) {
                    hasNonTrivialDivisor = true
                    break
                }
                d += 2
            }
            !hasNonTrivialDivisor 
        }
    }

    // print result
    val neg = if (isPrime) "" else " not"
    println("$n is$neg prime")
 }