Game programming in Unix

Hi there I''ve started taking a course in C a few months ago (well actually 2 months ago) and i now have a project to hand in I thought I''d do a simple games program since i hardly have much time left. I decided to do a simple snakes game on a bmp background (like a painting or something... just to make it look good) and then spend most of the time doing a graphical intro and stuff anyway i haven''t put in the picture yet (and am still not sure if its possible) but im having problems randomly generating dots on the screen can anybody help? Thanx