public static IEngine GetCarEngine(string choice) { IEngine carEngine = null; switch (choice) { case "1": carEngine = new V4Engine(); carEngine.SetEngineType(TypeOfEngine.V4); carEngine.SetMaximumSpeed(100); break; case "2": carEngine = new V8Engine(); carEngine.SetEngineType(TypeOfEngine.V8); carEngine.SetMaximumSpeed(200); break; case "3": carEngine = new GLXEngine(); carEngine.SetEngineType(TypeOfEngine.GLX); carEngine.SetMaximumSpeed(80); break; } return carEngine; }