I would suggest that a good place to start would be to go back thru the notes for the course where you were set this problem. They will either cover the subject in detail or point you at further reading that will help you.

If this isn't the case then you should probably go back to the lecturer and ask for further guidance.

--
<http://www.dave.org.uk>

"The first rule of Perl club is you don't talk about Perl club."