Cristi - 2011-11-14

So I'm supposed to make an alarm system using at least two classes. The
instructions I received are as follows "Make program which demonstrates Alarm
using at least two classes: Sensor (read) inside the loop and Siren (print).
Sensor read Alarm y(es)/n(o)? and Siren prints "Alarm!" if Alarm situation is
true otherwise it prints "ok"."

I have little to no clues on how to do it even though I do understand what
classes are. Can someone help? hints of any kind are welcomed.