PrimaEsercitazione.scala

/**
 * Created by sam on 17/09/15.
 */
object PrimaEsercitazione {

  def main(args: Array[String]) {



    println("Distance test:")
    val point1: (Double, Double) = (1d, 2d)
    val point2: (Double, Double) = (2d, 2d)
    val distance: Double = PointDistance.eval(point1, point2)
    println(s"Distance $point1 to $point2 = $distance")


    println("\n Equation test:")

    val verticalEq = LineEquation((1d,2d),(1d,4d))
    println(verticalEq)

    val defaultEq = LineEquation((1d,1d),(2d,2d))
    println(defaultEq)
    val defFunct: (Double) => Double = defaultEq.asFunction()


    println("\n Inclusion test: ")

    val isIn = defFunct(3d).equals(3d)
     println("(3,3) is in? " + isIn)

    val notIn = defFunct(4d).equals(3d)
    println("(4,3) is in? " + notIn)

  }

}

object PointDistance {

  def eval(point1: Tuple2[Double,Double],point2: Tuple2[Double,Double]) = {

    Math.sqrt(Math.pow(point1._1 - point2._1, 2) + Math.pow(point1._2 - point2._2, 2) )

  }

}

object LineEquation{

  def apply(a:Double,b:Double): LineEquation ={
    new LineEquation(a,b)
  }

  def apply(point1: Tuple2[Double,Double],point2: Tuple2[Double,Double]): LineEquation ={

    val y = point2._2 - point1._2
    val x = point2._1 - point1._1
    val a = y / x

    point1._1 - point2._1 match {

      case 0d => new LineEquation(0,point1._1)

      case _ =>  new LineEquation(a,point2._2 - a* point2._1)

    }
  }

}

class LineEquation(val a:Double,val b:Double){

  override def toString: String = s" y = $a * x + $b"

  def asFunction():Double => Double =  { x:Double => x * a + b }

}