How to generate codes

Hi,

I want to generate different codes in my program.

For Example: I want to dispaly the code from F00A with sno starting from 01.
F00A01
F00A02
.....
.....
F00A0n
If I Change F00A into F00B it generate sno again from 01.
F00B01
F00B02
......
......
F00B0n

How can I generate this type of codes.

I think you may need to add more information to elucidate what you're trying to do.