A student writes:

        Hey Dr. Patt, can we assume that each item in the array 
        will not appear more than once?  That is, will there only 
        be one 'b' and one 'c'?
        <<name withheld to protect one who does not read my email>>

Hey, Mr. Student!  Can I assume you did not get a chance to read 
the email message I sent about a half hour ago that dealt with a 
student's question about the "other 10 letters"?

Meanwhile, do you think your question is something we might have
anticipated?  If so, do you think we would have included something 
on the assignment page that would have immediately answered your 
question for you?

Nonetheless, I am delighted that you are working on the program
Monday night, and I am looking forward to you completing it in
an A+ way.

Good luck.
Yale Patt