/// <summary> /// Process one request. /// Must be one of: '+', '-', '/', '*' or a number in a double format. /// </summary> /// <param name="request"></param> public void ProcessSingleRequest(string request) { int size = data.GetSize(); switch (request) { case "+": case "-": case "*": case "/": if (size < 2) { ProcessError(request, 2); return; } ProcessAction(request); break; case "_": if (size == 0) { ProcessError(request, 1); return; } data.RemoveElement(); break; default: double number = Double.Parse(request); data.InsertElement(number); break; } }