The part of the assignment to pay attention to is this one (in terms of providing the biggest hint) ...
(only + and - operators allowed)
"+" and "-" has the same precedence. And without the other operators, there is no need to worry about the Order of Evaluation. The parsing can simply be done by going left to right, using a scanner, and a case statement in a loop.
Henry
[ February 04, 2008: Message edited by: Henry Wong ]