vulgar-fraction-sample.scala

import scala.annotation.tailrec

case class VulgarFraction(counter: Int, denominator: Int) {

  def toFloat = counter.toFloat / denominator
  def toInt = counter / denominator

  override def toString() = counter + "/" + denominator

  @tailrec
  private def gcd(a: Int, b: Int): Int = b match {
    case 0 => a
    case _ => gcd(b, (a % b))
  }

  private def simplify = gcd(counter, denominator) match {
    case d if d > 1 => VulgarFraction(counter / d, denominator / d)
    case _ => this
  }

  def +(that: VulgarFraction) =
    VulgarFraction(counter * that.denominator + that.counter * this.denominator, denominator * that.denominator)
      .simplify

  def -(that: VulgarFraction) =
    VulgarFraction(counter * that.denominator - that.counter * this.denominator, denominator * that.denominator)
      .simplify

  def *(that: VulgarFraction) =
    VulgarFraction(counter * that.counter, this.denominator * that.denominator)
      .simplify

  def /(that: VulgarFraction) =
    VulgarFraction(counter * that.denominator, this.denominator * that.counter)
      .simplify
}

object VulgarFraction {
  implicit def valueOf(in: Int) = VulgarFraction(in, 1)
}