Some psuedocode that helped me write a little program to do it:

1. choose files for copying (read a directory, for example)
2. loop though those existing files
3. open one of those files for reading
4. open a target file for writing
5. while files exist for reading
6.....print to target
7. close directory

or....

use built-in "cp" command from your OS.

Hope this helps!