I wasn't sure where to post this question but I hope its appropriate here ...

If anyone has studied this book...I'm confused on chapter 0.2.2 which mentions compiling (which is fine). Then suddenly mentions a program command cc mysource.c and explains that it's meant to out put a.out? Its not clear what the program is or where its come from? I checked to see if it was on the CD ROM that comes with the book but its not there either?