public void UPDATECALCULATION()
        {
            Console.WriteLine("=====================================================");
            Console.WriteLine("\n\tUPDATE CALCULATION DATA");
            Console.WriteLine("=====================================================");


login:
            String firstname, lastname;

            Console.Write("\n\tPlease Input First Name  :");
            firstname = Console.ReadLine();
            Console.Write("\n\tPlease Input Last Name   :");
            lastname = Console.ReadLine();

            try
            {
                Calculation respond = DataSet.CalculationList.Find(r => (r.FirstName == firstname) && (r.LastName == lastname));
                Console.WriteLine("=====================================================");
                Console.WriteLine("\n\tWHAT DO YOU WANT UPDATE?");
                Console.WriteLine("=====================================================");
                Console.WriteLine("*****************************************************");
                Console.WriteLine("\tA.Update Firstname:");
                Console.WriteLine("\tB.Update LastName:");
                Console.WriteLine("\tC.Update Position:");
                Console.WriteLine("\tD.Update No. of Day's Work:");
                Console.WriteLine("\tE.Update Daily Rate:");
                Console.WriteLine("\tF.Update Deduction:");
                Console.WriteLine("*****************************************************");
                Console.Write("\n\tWhat Is Your Choice?:    ");
                string Change = Console.ReadLine().ToString();

                if (Change == "A" || Change == "a")
                {
                    Console.Write("\tUpdate First Name    : ");
                    respond.FirstName = Console.ReadLine().ToString();
                }
                else if (Change == "B" || Change == "b")
                {
                    Console.Write("\tUpdate Last Name     : ");
                    respond.LastName = Console.ReadLine().ToString();
                }
                else if (Change == "C" || Change == "c")
                {
                    Console.Write("\tUpdate Position   :    ");
                    respond.Position = Console.ReadLine().ToString();
                }
                else if (Change == "D" || Change == "d")
                {
                    Console.Write("\tUpdate No. of day's Work : ");

                    respond.NumDays = int.Parse(Console.ReadLine());
                }
                else if (Change == "E" || Change == "e")
                {
                    Console.Write("\tUpdate Daily Rate: ");
                    respond.DailyRate = int.Parse(Console.ReadLine());
                    respond.Salary    = respond.NumDays * respond.DailyRate;
                }
                else if (Change == "F" || Change == "f")
                {
                    Console.Write("\tInput Update Deduction:");
                    respond.Deduction = double.Parse(Console.ReadLine());
                    respond.NetPay    = respond.Salary - respond.Deduction;
                }
                else
                {
                    Console.Write("\n\tInvalid Update");
                }
                Console.WriteLine("=====================================================");
                Console.WriteLine("\n\t\tYour data has been updated!...");
                Console.WriteLine("=====================================================");

                {
                    respond.Salary = respond.NumDays * respond.DailyRate;
                    respond.NetPay = respond.Salary - respond.Deduction;

                    Console.Read();
                }
            }

            catch
            {
                Console.Clear();
                Console.WriteLine("\t\t\t\t\nInvalid Credentials !!!");
                goto login;
            }


            Console.Write("\n\tPress any key to Continue......");

            Console.ReadLine();
            Console.Clear();
            LoginHome(lastname);;
        }
        public void DELETECALCULATION()
        {
            Program p = new Program();
            Delete  d = new Delete();

login:
            String lastname, firstname;

            Console.WriteLine("=====================================================");
            Console.WriteLine("\n\tDELETE CALCULATION DATA");
            Console.WriteLine("=====================================================");
            Console.Write("\tFirst Name   :   ");
            firstname = Console.ReadLine();
            Console.Write("\tLast Name    :   ");
            lastname = Console.ReadLine();

            try
            {
                Calculation respond = DataSet.CalculationList.Find(r => (r.FirstName == firstname) && (r.LastName == lastname));

                Console.WriteLine("**************** OPTION ***************");
                Console.WriteLine("\n\tPress D(delete)");
                Console.WriteLine("\n\tPress C(cancel)");
                Console.WriteLine("***************************************");
                Console.Write("\n\tCHOOSE OPTION    :   ");
                string choice = Console.ReadLine().ToString();


                switch (choice)
                {
                case "D":
                case "d":
                    d.CLEAN(respond);
                    Console.WriteLine("\n\tYour data Has Been Deleted!!!     Thank You..");

                    Console.Write("\n\tPress any key to Continue......");

                    Console.ReadLine();
                    Console.Clear();
                    p.LoginHome(lastname);
                    Console.Clear();
                    Console.ReadLine();


                    break;

                case "C":
                case "c":
                    break;

                default:

                    Console.Write("invalid input");
                    break;
                }
                ;

                Console.Read();
            }
            catch
            {
                Console.Clear();
                Console.WriteLine("\t\t\t\t\t\nInvalid Credentials !!!");
                goto login;
            }
        }