I am currently learning C++ at ITT, and I have been using their class book as well as other books to learn more about the langauge. In doing so, I have come across some inconsistencies in what the authors think is important.
My class book by Walter Savitch makes no real references to 'unsigned' variables. Another book by Jesse Liberty uses 'unsigned' variables in just about all of his examples. It doesn't save any memory by declaring an integer 'unsigned', so why bother?