//　試割法．定義通り

import Math._

def isPrime(num: Int): Boolean = {
  def func(num : Int):  Boolean = num match {
    case 2 =>  true
    case n if n < 2 => false
    case n if n%2 == 0 =>  false
    case n => loop(n, 3)
  }

  def loop(m : Int, i: Int): Boolean = (m , i) match {
    case (m, i) if m%i == 0 => false
    case (m, i) if pow(i, 2) > m => true
    case (m, i) => loop(m, i + 2)
  }

  func(num)
}

val result = isPrime(100000000)