public static void Test() { GSM phone = new GSM("Samsung", "Galaxy S3"); //Add calls GSMCallHistoryTest.Calls = new List <Calls> { new Calls(new DateTime(2015, 03, 17, 10, 32, 23), "0887591529", 35), new Calls(new DateTime(2015, 03, 17, 11, 32, 23), "0887595629", 56), new Calls(new DateTime(2015, 03, 17, 13, 32, 23), "0887576529", 39) }; foreach (Calls call in GSMCallHistoryTest.Calls) { phone.AddCall(call); } GSMCallHistoryTest.PrintInfoCalls(GSM.CallHistory); Console.WriteLine("Total price is {0:F2}", GSM.CalculateTotalPrice(0.37)); RemoveLongestCall(phone, GSM.CallHistory); Console.WriteLine("Total price without the longest call is {0:F2}", GSM.CalculateTotalPrice(0.37)); phone.ClearCallHistory(); }