fizz-buzz.scala

/**
  * Write a program that prints the numbers from 1 to 100.
  * But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz".
  * For numbers which are multiples of both three and five print "FizzBuzz".
  */
object FizzBuzzApp extends App {
  sealed trait Foo
  case object Fizz extends Foo
  case object Buzz extends Foo
  case object FizzBuzz extends Foo
  case class Neither(s: Int) extends Foo

  object Foo {
    val multOf3: Int => Boolean = (n: Int) => n % 3 == 0
    val multOf5: Int => Boolean = (n: Int) => n % 5 == 0
    val multOf5And5: Int => Boolean = (n: Int) => multOf3(n) && multOf5(n)

    def apply(int: Int): Foo =
      if  (multOf5And5(int)) FizzBuzz
      else if (multOf5(int)) Buzz
      else if (multOf3(int)) Fizz
      else                   Neither(int)

    import cats.instances.int._
    implicit val showFoo: Show[Foo] = Show.show[Foo] {
      case Fizz => "Fizz"
      case Buzz => "Buzz"
      case FizzBuzz => "FizzBuzz"
      case Neither(i) => i.show
    }
  }

  def main: Unit =
    (1 to 100)
      .toList
      .foreach { x => println(Foo(x).show) }

  main
}

//1
//2
//Fizz
//4
//Buzz
//Fizz
//7
//8
//Fizz
//Buzz
//11
//Fizz
//13
//14
//FizzBuzz
//16
//17
//Fizz
//19
//Buzz
//Fizz
//22
//23
//Fizz
//Buzz
//26
//Fizz
//28
//29
//FizzBuzz
//31
//32
//Fizz
//34
//Buzz
//Fizz
//37
//38
//Fizz
//Buzz
//41
//Fizz
//43
//44
//FizzBuzz
//46
//47
//Fizz
//49
//Buzz
//Fizz
//52
//53
//Fizz
//Buzz
//56
//Fizz
//58
//59
//FizzBuzz
//61
//62
//Fizz
//64
//Buzz
//Fizz
//67
//68
//Fizz
//Buzz
//71
//Fizz
//73
//74
//FizzBuzz
//76
//77
//Fizz
//79
//Buzz
//Fizz
//82
//83
//Fizz
//Buzz
//86
//Fizz
//88
//89
//FizzBuzz
//91
//92
//Fizz
//94
//Buzz
//Fizz
//97
//98
//Fizz
//Buzz