public static void TestCallHistory() { GSM motorola = new GSM("nexus", "Motorola", 500, "comapny phone", new Battery(BatteryType.NiCd), new Display(5, 2000)); GSM newBrand = new GSM("SSD", "MegaHyper"); motorola.AddCall(new Call("12/03/2015", "05:34", "0889888888", 100)); motorola.AddCall(new Call("02.02.2012", "12:34", "0999999999", 140)); motorola.AddCall(new Call("12.30.2012", "00:34", "0999999999", 12)); ShowCalls(motorola.calls); Console.WriteLine("The Total Price is {0}", motorola.CalculateTotalPrice()); motorola.FindAndRemoveLongestCall(); Console.WriteLine("Longest call now removed"); Console.WriteLine("The Total Price is {0:F2}", motorola.CalculateTotalPrice()); motorola.ClearHistory(); Console.WriteLine("Call history deleted"); }