public GSMCallHistoryTest() { phone.AddtoHistory(DateTime.Now, 45454, 120); phone.AddtoHistory(DateTime.Now, 45454, 120); phone.AddtoHistory(DateTime.Now, 45454, 120); phone.AddtoHistory(DateTime.Now, 45454, 130); phone.AddtoHistory(DateTime.Now, 45454, 120); foreach (var call in phone.CallHistory) { Console.WriteLine(call.PrintCallHistory()); } Console.WriteLine("Total price: " + phone.CalculatePhoneBill()); var longestCall = phone.CallHistory.Max(r => r.DurationOfCall); phone.CallHistory.RemoveAll(r => r.DurationOfCall == longestCall); Console.WriteLine("Total price: " + phone.CalculatePhoneBill()); foreach (var call in phone.CallHistory) { Console.WriteLine(call.PrintCallHistory()); } }