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