DoRightt

interface State {
  insertQuarter(): any;
  ejectQuarter(): any;
  turnCrank(): any;
  dispense(): any;
}

class SoldState implements State {
  gumBallMachine: GumBallMachine;

DoRightt

interface Iterator {
  next(): Object;
  hasNext(): boolean;
}

class DinnerMenuIterator implements Iterator {
  items: MenuItem[];
  position: number = 0;

  constructor(items: MenuItem[]) {

DoRightt

class CaffeineBeverage {
  final prepareRecipe(): void {
    this.boilWater();
    this.brew();
    this.pourinCup();
    if (this.customerWantsCondiments()) {
      this.addCondiments();
    }
  }

DoRightt

class Amplifier {
  tunner: Tunner;
  dvdPlayer: DvdPlayer;
  cdPlayer: CdPlayer;

  constructor(tunner: Tunner, dvd: DvdPlayer, cd: CdPlayer) {
    this.tunner = tunner;
    this.dvdPlayer = dvd;
    this.cdPlayer = cd;
  }

DoRightt

interface Duck {
  quack(): void;
  fly(): void;
}

interface Turkey {
  gobble(): void;
  fly(): void;
}

DoRightt

interface Command {
  execute(): void;
  undo(): void;
}

class Light {
  room: string;

  constructor(room: string) {
    this.room = room;

DoRightt

abstract class Beverage {
  description: string = "Unknown beverage";

  getDescription() {
    return this.description;
  }

  cost(): number {
    return 0;
  }

DoRightt

interface QuackBehavior {
  quack(): void;
}

interface FlyBehavior {
  fly(): void;
}

class Quack implements QuackBehavior {
  quack(): void {

DoRightt

class Pizza {
  bake() {}
  prepare() {}
  box() {}
  cut() {}
}

class CheesePizza extends Pizza {}

class PepperoniPizza extends Pizza {}

DoRightt

abstract class Pizza {
  name: string;
  dough: Dough;
  sauce: Sauce;
  veggies: Veggies;
  cheese: Cheese;
  pepperoni: Pepperoni;
  clams: Clams;
  toppings: string[] = ["Extra Mozzarella"];