September 2017 Update

Task/Arithmetic-Complex/Kotlin/arithmetic-complex.kotlin

@@ -0,0 +1,39 @@
+class Complex(private val real: Double, private val imag: Double) {
+    operator fun plus(other: Complex) = Complex(real + other.real, imag + other.imag)
+
+    operator fun times(other: Complex) = Complex(
+        real * other.real - imag * other.imag,
+        real * other.imag + imag * other.real
+    )
+
+    fun inv(): Complex {
+        val denom = real * real + imag * imag
+        return Complex(real / denom, -imag / denom)
+    }
+
+    operator fun unaryMinus() = Complex(-real, -imag)
+
+    operator fun minus(other: Complex) = this + (-other)
+
+    operator fun div(other: Complex) = this * other.inv()
+
+    fun conj() = Complex(real, -imag)
+
+    override fun toString() =
+        if (imag >= 0.0) "$real + ${imag}i"
+        else "$real - ${-imag}i"
+}
+
+fun main(args: Array<String>) {
+    val x = Complex(1.0, 3.0)
+    val y = Complex(5.0, 2.0)
+    println("x     =  $x")
+    println("y     =  $y")
+    println("x + y =  ${x + y}")
+    println("x - y =  ${x - y}")
+    println("x * y =  ${x * y}")
+    println("x / y =  ${x / y}")
+    println("-x    =  ${-x}")
+    println("1 / x =  ${x.inv()}")
+    println("x*    =  ${x.conj()}")
+}