*   not all loops are count-controlled!

    ...some are EVENT-controlled -- continuing until some event happens;
    ...we're going to a discuss a particular kind of event-controlled
       loop, that has an interesting pattern different from a
       count-controlled loop: sentinel-controlled loop

       *   a loop where where data is accepted until a special
           non-data value, called the SENTINEL, is read in;

       *   (it DOES help, for this loop, if there is a reasonable
           choice of sentinel value, reasonable to distinguish from
	   "real" data;)

       *   a key point here: you don't WANT to the treat that
           sentinel, when encountered, as "real" data...

*   that leads to the following pseudocode for the CLASSIC sentinel-controlled
    loop (and you are expected to use this approach in this class):
    
    get first piece of data

    while (it isn't the sentinel)
    {
        handle data

        get next piece of data
    }

*   see spicy_levels.cpp
    (which uses a sentinel-controlled loop)

*   biggest drawback here is when you don't happen to have a reasonable
    sentinel value in a given setting...

*   here is a variant for such a situation --
    it isn't a sentinel-controlled loop, because the data read in
    ISN'T determining when the loop stops --
    BUT it has a similar structure:

    (what I call the "question" approach...)

    ask user if they want to go on

    while the answer is yes
    {
        get the data
        handle the data

        ask user if they want to go on
    }

*   example of this approach:
    see main function in spicy_q.cpp

LAB EXERCISE:
write a main function
that uses cheer (Week 11, Lecture 2)
and uses a sentinel-controlled loop to ask the user, over and over,
    how many hips they'd like to see,
    and then calls cheer for that many hips,
    until the user enters a negative number of hips;
when you are done, or at 11:50, whichever comes first,
    submit your .cpp and .h files using ~st10/131submit with a HW number of 13