The following lines show the code for the Animal
base class in Swift. The class header doesn't specify a base class, so this class will become our base class for the other classes:
public class Animal { public static var numberOfLegs: Int { get { return 0; } } public static var averageNumberOfChildren: Int { get { return 0; } } public static var abilityToFly: Bool { get { return false; } } public var age: Int init(age : Int) { self.age = age print("Animal created") } public static func printALeg() { preconditionFailure("The pringALeg method must be overriden") } public func printLegs() { for _ in 0..<self.dynamicType.numberOfLegs { self.dynamicType.printALeg() } print(String()) } public static func printAChild()...