End of 'Classes'

src/aquarium/Aquarium.kt

@@ -1,14 +1,16 @@
 package aquarium
 
-class Aquarium(var length: Int = 100, var width: Int = 20, var height: Int = 40) {
+import kotlin.math.PI
 
-    var volume: Int
+open class Aquarium(var length: Int = 100, var width: Int = 20, var height: Int = 40) {
+
+    open var volume: Int
         get() = width * height * length / 1000
         set(value) {
             height = (value * 1000) / (width * length)
         }
 
-    var water = volume * 0.9
+    open var water = volume * 0.9
 
     constructor(numberOfFish: Int): this() {
         val water = numberOfFish * 2000 // cm3
@@ -16,4 +18,15 @@ class Aquarium(var length: Int = 100, var width: Int = 20, var height: Int = 40)
         height = (tank / (length * width)).toInt()
     }
 
+}
+
+class TowerTank(): Aquarium() {
+    override var water = volume * 0.8
+
+    override var volume: Int
+        get() = (width * height * length / 1000 * PI).toInt()
+        set(value) {
+            height = (value * 1000) / (width * length)
+        }
+
 }

src/aquarium/Fish.kt

@@ -0,0 +1,23 @@
+package aquarium
+
+abstract class Fish {
+    abstract val color: String
+}
+
+class Shark: Fish(), FishAction {
+    override val color = "grey"
+    override fun eat() {
+        println("hunt and eat fish")
+    }
+}
+
+class Plecostomus: Fish(), FishAction {
+    override val color = "gold"
+    override fun eat() {
+        println("munch on algae")
+    }
+}
+
+interface FishAction {
+    fun eat()
+}

src/aquarium/decorations/decorations.kt

@@ -0,0 +1,13 @@
+package aquarium.decorations
+
+fun main(args: Array<String>) {
+    makeDecorations()
+}
+
+fun makeDecorations() {
+    val d1 = Decorations("granite")
+    val d2 = Decorations("slate")
+    val d3 = Decorations("slate")
+}
+
+data class Decorations(val rocks: String) {}

src/aquarium/main.kt

@@ -30,3 +30,10 @@ private fun buildAquarium() {
         "height: ${myAquarium2.height}"
     )
 }
+
+fun makeFish() {
+    val shark = Shark()
+    val pleco = Plecostomus()
+
+    println("Shark ${shark.color} \n Plecostomus: ${pleco.color}")
+}