A recusive algorithm or sample C or C++ or java program code that can
print out all the possible combination order of a character string.
For ex: give "ATM", will print out:
"ATM", "TAM", "TMA", "MAT", "MTA", "AMT". (n! number orders, n is the
nubmer of characters in the string).

I have two such algorithms for you, both written in C.  They both do
what you need, although you can easily modify them if need be.  Code
is from SourceForge.net and is under the GNU General Public License.


Permutation Generator
This one works, but there could definately be some cleanup done to the
code.  It is commented a little, but easy to follow.
http://sourceforge.net/snippet/detail.php?type=snippet&id=100209

String Permutation Generator
This is a more elegant recursive function, with fewer lines of code
than the one above.  The comments allow for ease of use and
modification, although I see no real reason to need to modify this
snippet.
http://sourceforge.net/snippet/detail.php?type=snippet&id=100376


I hope that helps with your problem!
Xargon-ga