unsafe_ints.scala

object types {

 def divide(i: Int): Int = (i/5).toInt

  def subtract(i: Int): Int = i - 10

  def multiply(i: Int): Int = i * -1

  def allOK(i: Int):Int = {
   val s1 =divide(i)
   val s2 = subtract(s1)
   val s3 = multiply(s2)
   s3
  }

def allBAD(i: Int):Int = {
   val s1 =divide(i)
   val s2 = multiply(s1)
   val s3 = subtract(s2)
   s3
  }
  
}

/*
scala> types.allOK(1)
res19: Int = 10

scala> types.allBAD(1)
res20: Int = -10 // A bug!
*/