For the view command, edit command, delete command, it is stated in the user guide, that the one of the parameter it accepts is a positive integer for the index, however 0 can also be considered a positive integer.
You do specify in the user guide that positive integer 1, 2, 3,....
Hoewever, I think it will be better if you can specify that the parameter index takes in integer values greater than or equal to 1.
For the view command, edit command, delete command, it is stated in the user guide, that the one of the parameter it accepts is a positive integer for the index, however 0 can also be considered a positive integer.
You do specify in the user guide that positive integer 1, 2, 3,....
Hoewever, I think it will be better if you can specify that the parameter index takes in integer values greater than or equal to 1.