How to get a list of files extensions of a folder

[L0v3craft]

Hi guys, i need of a little program that given a folder(with files and folders inside) can gives to me the list of the extensions of the existing files inside that folder.

Example: i give to the program the directory of some installed game and it gives to me a report like this:

Extensions of present files:

.exe
.dll
.mp3
.bik
.pak
.assets
.resS
and so on

I mean, i don't want get a list of all files, i want only get a list of the extensions(but wrote only one time like in my example).

The purpose of a program like this is that i can get in few seconds the list of the extensions of all existing files in a given folder, so in the cases when a game has 20/30k files i don't must check every folder/subfolder or however i will not check(slowly) a list of 40k files to check every extensions of the present files. With a software like this i can get in few seconds what i want know and i can test different compression methods for every different type/extension of the files present in the game folder.

Sorry for my bad english but i don't find better words to explain this

A bat file that can do something like this should be enough for me too.

I'm sure that "felice2011" is able to create something like this, thank you!