/*
 * File: primes.kt
 * Compilation: kotlinc primes.kt
 * Execution: kotlin PrimesKt limit
 *    where limit is a positive integer
 * Purpose: Prints all primes <= limit, 10 primes per line.
 * Author: SS
 */

// return true iff n is an odd prime
fun isOddPrime(n: Int): Boolean {
    var d = 3
    while (d * d <= n) {
        if (n % d == 0)
            return false
        d += 2
    }
    return true
}

// return true iff n is prime
fun isPrime(n: Int) = when {
    n < 2 -> false
    n == 2 -> true
    n % 2 == 0 -> false
    else -> isOddPrime(n)
}

const val PRIMES_PER_LINE = 10
fun main(args: Array<String>) {
    val limit = args[0].toInt()
    var count = 0
    for (n in 1..limit)
        if (isPrime(n)) {
            count = (count+1) % PRIMES_PER_LINE
            val specifier = if (count == 0) "%8d%n" else "%8d"
            print(specifier.format(n))
        }
    println()
}