Should I alert the user that an exception has occurred or just let the code keep running?
A.
If you've written code to handle the specific exception, there's probably no need to tell the user about it. However, if an exception occurs that the code doesn't know how to address, you should provide the user with the exception information so that they can report the problem accurately so that you can fix it.
Q.
Should I comment every statement in my application?
A.
Probably not. However, consider commenting every decision-making and looping construct in your program. Such sections of code are usually pivotal to the success of the procedure, and what they do isn't always obvious.