break the problem up into smaller problems. (hopefully the book you bought is using java 1.5)
1) and 2), look up how to accept import from the keyboard(hint: Scanner!)
2) in what way would you check(keyword: check) if it's a certain character? think what kind of statement that would use
3) and 4) simply develop seperate cases based on the results of the check.
like:
Code:
if( this is true) then do this
else if (that is true) then do that
5) is just telling you to use a loop to do your calculations, (and not recursively)
look in the java API for methods if your book doesn't lay them out.
http://java.sun.com/j2se/1.5.0/docs/api/
that site can be your best friend sometimes.
and you won't learn much if you ask for all the code and have someone email it. you HAVE to be able to do it on your own, or else completing the exercise is worthless.
good luck!