private static void ProcessUserInput()
        {
            while (true)
            {
                string input  = Console.ReadLine();
                int    option = 1;

                if (int.TryParse(input, out option))
                {
                    APP_OPTIONS appOption = (APP_OPTIONS)option;

                    if (appOption == APP_OPTIONS.QUIT)
                    {
                        break;
                    }
                    else
                    {
                        ProcessAppOption(appOption);
                        PrintSeparator();
                        ShowAppOptions();
                    }
                }
                else
                {
                    Console.WriteLine("Enter a valid option");
                }
            }
        }
        private static void ProcessAppOption(APP_OPTIONS appOption)
        {
            Option option = null;

            switch (appOption)
            {
            case APP_OPTIONS.MAGIC_SQUARE:
                option = new MagicSquareOption();
                break;

            case APP_OPTIONS.PARABOLA_GRAPH:
                option = new ParabolaChartOption();
                break;

            case APP_OPTIONS.BAR_CHART:
                option = new BarChartOption();
                break;

            default:
                Console.WriteLine("Not a valid option");
                break;
            }

            if (option != null)
            {
                option.ExecuteOption();
            }
        }