September 2017 Update

Task/Abstract-type/Kotlin/abstract-type.kotlin

@@ -0,0 +1,55 @@
+// version 1.1
+
+interface Announcer {
+    fun announceType()
+
+    // interface can contain non-abstract members but cannot store state
+    fun announceName() {
+        println("I don't have a name")
+    }
+}
+
+abstract class Animal: Announcer {
+    abstract fun makeNoise()
+
+    // abstract class can contain non-abstract members
+    override fun announceType() {
+        println("I am an Animal")
+    }
+}
+
+class Dog(private val name: String) : Animal() {
+    override fun makeNoise() {
+       println("Woof!")
+    }
+
+    override fun announceName() {
+       println("I'm called $name")
+    }
+}
+
+class Cat: Animal() {
+    override fun makeNoise() {
+       println("Meow!")
+    }
+
+    override fun announceType() {
+       println("I am a Cat")
+    }
+}
+
+fun main(args: Array<String>) {
+    val d = Dog("Fido")
+    with(d) {
+        makeNoise()
+        announceType()  // inherits Animal's implementation
+        announceName()
+    }
+    println()
+    val c = Cat()
+    with(c) {
+        makeNoise()
+        announceType()
+        announceName()  // inherits Announcer's implementation
+   }
+}