static public void ProgramMode(string keyWord) { DocumentProgram DP; switch (keyWord) { case "basic": DP = new DocumentProgram(); DP.OpenDOcument(); DP.EditDocument(); DP.SaveDocument(); break; case "pro": DP = new ProDocumentProgram(); DP.OpenDOcument(); DP.EditDocument(); DP.SaveDocument(); break; case "expert": DP = new ExpertDocumentProgram(); DP.OpenDOcument(); DP.EditDocument(); DP.SaveDocument(); break; default: Console.WriteLine("Invalid choice !"); break; } }