Though this chapter is comparatively short, it covers broader ground than first appears, and for this reason it is important readers practice file I/O (input/output) carefully. Reading and writing information to files is important, mainly because it extends a program beyond merely running once to allowing potentially many sessions to be run, saved, and then resumed. It's not an especially difficult subject in the overall scheme of things, but nonetheless it is difficult to master the art of game programming without understanding how it works. The next chapter explores more detailed applications of C++ that are particularly useful in the world of game development.