Implementation of complex numbers from Czech Scala Enthusiasts coding dojo held on April 9th 2013

ComplexNumber.scala

class ComplexNumber private (val x: Int, val y: Int) {
  
  def +(c: ComplexNumber) = ComplexNumber(x + c.x, y + c.y)

  def *(c: ComplexNumber) = ComplexNumber((x * c.x) - (y * c.y), (y * c.x) + (x * c.y))
  
  // higher-order method
  def transform(f: ComplexNumber => ComplexNumber) = f(this)

  override def toString = s"$x + ${y}i"

  override def equals(obj: Any): Boolean = obj match {
    case c: ComplexNumber => x == c.x && y == c.y
    case _ => false
  }

  override def hashCode(): Int = 31 + (31 * x + 31 * y)
}

object ComplexNumber {
  
  val i = ComplexNumber(0, 1)
  
  def apply(x: Int, y: Int) = new ComplexNumber(x, y)
  
  implicit def int2Complex(i: Int) = ComplexNumber(i, 0)

}