static void Main(string[] args)
        {
            GSM phone1 = new GSM("lala", "sumsAng");

            phone1 = new GSM("lol", "krusha", "suparMan", 9999, new Battery(Battery.batteryModel.LiIon, 2, 1));
            Console.WriteLine(phone1.ToString());
            phone1 = new GSM("ROFL", "kazanlak ltd", "batMan", 9999, new Battery(Battery.batteryModel.NiCd, 999, 9999));
            Console.WriteLine(phone1.ToString());
        }
 static void Main(string[] args)
 {
     GSM phone = new GSM("lala", "sumsAng");
     Console.WriteLine(phone.ToString());
     phone = new GSM("lala", "sumsAng", "batman");
     Console.WriteLine(phone.ToString());
     phone = new GSM("lol", "krusha", "suparMan", 9999, new Battery("tuhla", 2, 1));
     Console.WriteLine(phone.ToString());
     phone = new GSM("lol", "krusha", "suparMan", 9999, new Display(5.5, 3));
     Console.WriteLine(phone.ToString());
 }
        static void Main(string[] args)
        {
            GSM phone = new GSM("lala", "sumsAng");

            Console.WriteLine(phone.ToString());
            phone = new GSM("lala", "sumsAng", "batman");
            Console.WriteLine(phone.ToString());
            phone = new GSM("lol", "krusha", "suparMan", 9999, new Battery("tuhla", 2, 1));
            Console.WriteLine(phone.ToString());
            phone = new GSM("lol", "krusha", "suparMan", 9999, new Display(5.5, 3));
            Console.WriteLine(phone.ToString());
        }
 static void Main(string[] args)
 {
     GSM phone1 = new GSM("lala", "sumsAng");
     phone1 = new GSM("lol", "krusha", "suparMan", 9999, new Battery(Battery.batteryModel.LiIon, 2, 1));
     Console.WriteLine(phone1.ToString());
     phone1 = new GSM("ROFL", "kazanlak ltd", "batMan", 9999, new Battery(Battery.batteryModel.NiCd, 999, 9999));
     Console.WriteLine(phone1.ToString());
 }