Thanks for all your responses folks. LZ77 is supposed to compress and decompress a file. It's one of the algorithm used in WinZip which compresses the file (to make the file size smaller) and decompresses it to it's original file. I am sorry if most of you didn't have a clue what it's all about but I can't really have a good explanation if you are not a coder. It uses a dictionary, sliding window and look ahead buffer. Does that make sense to you? Probably not! hahah.. it's like someone giving me a chemistry test. SMSainju and Echoes seem to have disappeared in Sajha. My program will ask for a file to be compressed and will create a compressed file. This program is only the compression part, I still need to write the decompression routine. Anyways, if anyone's out there for any help, please respond. Thanks bunch guys, LoGiN