Add all the A tasks

Task/Arithmetic-Complex/Scala/arithmetic-complex-1.scala

@@ -0,0 +1,35 @@
+package org.rosettacode
+
+package object ArithmeticComplex {
+  val i = Complex(0, 1)
+
+  implicit def fromDouble(d: Double) = Complex(d)
+  implicit def fromInt(i: Int) = Complex(i.toDouble)
+}
+
+package ArithmeticComplex {
+  case class Complex(real: Double = 0.0, imag: Double = 0.0) {
+    def this(s: String) =
+      this("[\\d.]+(?!i)".r findFirstIn s getOrElse "0" toDouble,
+           "[\\d.]+(?=i)".r findFirstIn s getOrElse "0" toDouble)
+
+    def +(b: Complex) = Complex(real + b.real, imag + b.imag)
+    def -(b: Complex) = Complex(real - b.real, imag - b.imag)
+    def *(b: Complex) = Complex(real * b.real - imag * b.imag, real * b.imag + imag * b.real)
+    def inverse = {
+      val denom = real * real + imag * imag
+      Complex(real / denom, -imag / denom)
+    }
+    def /(b: Complex) = this * b.inverse
+    def unary_- = Complex(-real, -imag)
+    lazy val abs = math.hypot(real, imag)
+    override def toString = real + " + " + imag + "i"
+
+    def i = { require(imag == 0.0); Complex(imag = real) }
+  }
+
+  object Complex {
+    def apply(s: String) = new Complex(s)
+    def fromPolar(rho:Double, theta:Double) = Complex(rho*math.cos(theta), rho*math.sin(theta))
+  }
+}

Task/Arithmetic-Complex/Scala/arithmetic-complex-2.scala

@@ -0,0 +1,26 @@
+scala> import org.rosettacode.ArithmeticComplex._
+import org.rosettacode.ArithmeticComplex._
+
+scala> 1 + i
+res0: org.rosettacode.ArithmeticComplex.Complex = 1.0 + 1.0i
+
+scala> 1 + 2 * i
+res1: org.rosettacode.ArithmeticComplex.Complex = 1.0 + 2.0i
+
+scala> 2 + 1.i
+res2: org.rosettacode.ArithmeticComplex.Complex = 2.0 + 1.0i
+
+scala> res0 + res1
+res3: org.rosettacode.ArithmeticComplex.Complex = 2.0 + 3.0i
+
+scala> res1 * res2
+res4: org.rosettacode.ArithmeticComplex.Complex = 0.0 + 5.0i
+
+scala> res2 / res0
+res5: org.rosettacode.ArithmeticComplex.Complex = 1.5 + -0.5i
+
+scala> res1.inverse
+res6: org.rosettacode.ArithmeticComplex.Complex = 0.2 + -0.4i
+
+scala> -res6
+res7: org.rosettacode.ArithmeticComplex.Complex = -0.2 + 0.4i