static void Main(string[] args) { Console.WriteLine( "Please, input the full filename(with path) of your file and press 'enter'. For example: \"c:\\C-small-practice.in\""); Console.Write("Or enter 'exit' to quit."); Console.WriteLine(Environment.NewLine); string input; do { input = Console.ReadLine(); if (string.IsNullOrEmpty(input)) { Console.WriteLine("Error! Please enter valid filename"); continue; } if (input.ToLower().Trim() == "exit") { return; } }while (string.IsNullOrEmpty(input)); try { var fileProvider = new FileProvider(new T9Converter()); var outputFilePath = fileProvider.FileHandling(new FileInfo(input)); Console.WriteLine("Done! Your output file is:" + outputFilePath.FullName); } catch (Exception e) { Console.WriteLine(e); } finally { Console.ReadKey(); } }