public GSMHistory(string model, PhoneManufacturer manufacturer, string owner, float price,
     BatteryEnumeration battery, DisplayEnumeration display)
     : base(model, manufacturer, owner, price, battery, display)
 {
     this.callHistory = new List<Call>();
 }
 public GSMStatic(string model, PhoneManufacturer manufacturer, string owner, float price,
     BatteryEnumeration battery, DisplayEnumeration display)
     : base(model, manufacturer, owner, price, battery, display)
 {
 }
 public string ToString(BatteryEnumeration battery, DisplayEnumeration display)
 {
     string phoneInfo = string.Format("Phone {0} {1}\r\nowned by {2}\r\nprice ${3:F2}\r\nbattery: {4}\r\ndisplay: {5}",
         base.Manufacturer, base.Model, base.Owner, base.Price, battery.ToString(), display.ToString());
     return phoneInfo;
 }
 public static BatteryEnumeration CreateBattery()
 {
     Console.WriteLine("Enter battery model");
     string batteryModel = Console.ReadLine();
     Console.WriteLine("Enter battery endurance in idle");
     float batteryHourIdle = float.Parse(Console.ReadLine());
     Console.WriteLine("Enter battery endurance in talk");
     float batteryHourTalk = float.Parse(Console.ReadLine());
     Console.WriteLine("Enter number code of battery type");
     byte batteryType = byte.Parse(Console.ReadLine());
     BatteryEnumeration battery = new BatteryEnumeration(batteryModel, batteryHourIdle, batteryHourTalk, (BatteryType)batteryType);
     return battery;
 }