Accessing files in sub directories

Hello

I am currently working on a project which scan a file and extracts relevant data from it. I have designed a program which does what I need and it works fine for one file. What I would like to know, is there way that my program can access a file in a particular directory, use it and then move to the next file in that directory. After using all the files in the directory then move to a subdirectory or another directory and so on. Some one mentioned globbing to me, but a search on google hasn`t really produced anything. Any help or ideas would be much appreciate.
Thank you.

Kind regards

You can find some example code that may be useful at http://sol-biotech.com/code/. Look for DirectoryListing.cpp for a POSIX version (with some bugs) or WinDirectoryListing.cpp for a Windows version.