We do not do your homework: it is set for a reason. It is there so that you think about what you have been told, and try to understand it. It is also there so that your tutor can identify areas where you are weak, and focus more attention on remedial action.
Try it yourself, you may find it is not as difficult as you think!
This really isn't difficult - just try it manually on a piece of paper, and work out what you have to do...then translate that to C. Start with the asterisks, because it's less to think about, and try to do just half the pattern:
When you have got that working, the rest should just fall into place.