While we are more than willing to help those that are stuck, that doesn't mean that we are here to do it all for you! We can't do all the work, you are either getting paid for this, or it's part of your grades and it wouldn't be at all fair for us to do it all for you.
So we need you to do the work, and we will help you when you get stuck. That doesn't mean we will give you a step by step solution you can hand in!
Start by explaining where you are at the moment, and what the next step in the process is. Then tell us what you have tried to get that next step working, and what happened when you did.
And from the little you have told us, the task as stated is not possible: there is no obvious link between yoru input of 0 and your output of 1 2 3 8, or 1 giving -1.
Go back to the assignment, and read it carefully - it almost certainly contains details you need to complete this - if not then you need to talk to whoever set the assignment and get a good deal of clarification.
Once you have a "proper question" sorted out, then if you are having problems getting started at all, then this may help: How to Write Code to Solve a Problem, A Beginner's Guide
But from what you show so far, nobody can do anything useful at all.