Complex number implementation in Scala with various features of Scala language as coded at Czech Scala Enthusiasts' Scala coding dojo on Apr 9, 2013

ComplexNumber

package com.czechscala.blank

class ComplexNumber private(val x: Int, val y: Int) {
  
  override def toString() = s"$x + ${y}i"
  
  override def equals(c: Any) =  c match {
    	case x : ComplexNumber => x.x == this.x && x.y == y  
    	case _  => false
  }
    
  override def hashCode() = 31 + 23 * this.x + 17 * this.y
  
  def add(c: ComplexNumber) = new ComplexNumber(this.x+c.x, this.y +c.y)
  
  def +(c: ComplexNumber) = add(c)
  
  def -(c: ComplexNumber) = add(ComplexNumber(-c.x,-c.y))
  
  def absoluteValue() : Int =  math.sqrt((x*x) - (y*y)).toInt
  
  def multiply(c: ComplexNumber) = ComplexNumber(x*c.x - y*c.y , x*c.y + y*c.x)
  
  def *(c: ComplexNumber) = multiply(c)
  
  def transform(f: ComplexNumber => ComplexNumber) = f(this) 
  
}

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

  def apply(abs: Int, alpha: Double) = new ComplexNumber((math.cos(alpha)*abs).toInt,(math.sin(alpha)*abs).toInt); 
  
  implicit def intToComplex(x: Int) = new ComplexNumber(x,0) 

}

ComplexNumberTest

package com.czechscala.blank

import org.scalatest.FunSuite
import ComplexNumber.{i,intToComplex}
 
class ComplexNumberTest extends FunSuite {
 
  test("complex number is set") {
    val c =  ComplexNumber(4,5)
    assert(c.x === 4)
    assert(c.y === 5)
  }
  
  test("complex number to string") {
    val c =  ComplexNumber(20, 10)
    assert(c.toString()==="20 + 10i")
  }

  test("complex number count") {
    val c1 = ComplexNumber(12, 31)
    val c2 =  ComplexNumber(1, -1)
    assert(c1 + c2 === ComplexNumber(13, 30))
  }
  
  test("numbers are equal"){
    val c1 =  ComplexNumber(12, 31)
    val c2 =  ComplexNumber(12, 31)
    assert(c1 === c2)
  }
  
  test("numbers aren't equal"){
    val c1 =  ComplexNumber(12, 31)
    val c2 =  ComplexNumber(12, -2)
    assert(c1 != c2)
  }
  
  test("number hash code"){
    val c =  ComplexNumber(1, 1)
    assert(c.## === 71)
  }
  
  test("get absolute value"){
    val c =  ComplexNumber(5, 3)
    assert(c.absoluteValue() === 4)
  }
  
  test("multiplication test"){
    val c1 =  ComplexNumber(5, 5)
    val c2 =  ComplexNumber(5, -5)
    assert(c1 * c2 === ComplexNumber(50,0))
  }
  
  test("dsl complex number test"){
    val c1 = 1 + 3*i
    assert(c1 === ComplexNumber(1,3))
  }
  
  
  test("list of complex numbers"){

     val c = 2 + 2*i
     
     val c1 = c.transform(n => n*i)
     
     assert(c1*c === -8 + 0*i)
  }
  
  test("list of complex numbers 2"){

     val c = 2 + 2*i
     
     val c1 = c.transform((n: ComplexNumber) => {n * (-1 +0*i)})
     
     assert(c1 === -2 -2*i)
  }
  
  
}