++! Now that you mention it, I remember using -n for running top through 'n' iterations of page refresh. There's also the 'batch mode' for passing output from top to other programs. Here's what my copy of manpage has to say about this:

-b : Batch mode operation
            Starts  top  in 'Batch mode', which could be useful for sending output from top to other programs
            or to a file.  In this mode, top will not accept input and runs until the iterations limit you've
            set with the '-n' command-line option or until killed.