Hi!

This MHK again with a handy BASIC program... It's a credit card number
verification proggy! With all features. Also, examining the source you will
understand the credit card serial number formation...
  This program was made and tested with MS-DOS QBASIC and it works under
GWBASIC as well. The core of this program was found from a little file
CS.BAS, which was quite simple (included also). No authorities were claimed
in the file so I modified and improved it. Anyway, I wish to thank whoever
made it on BASIC.
  Well, back to the program. I'm not sure if the 13 number VISA card serial
is verified the same way as 16 number one and what's the difference between
'em anyway, so don't trust the proggy when checking 13 number serials. I
will release a fixed version for the 13 number VISAs sometime.
  To use the the program, just fire up your BASIC and run a program. If you
find it useful, try compiling them to EXE.

NOTE:DON'T tell me BASIC is not for real men. I just can only "program" with
     that (but NOT meaning I am basic).


Error messages:

ERROR:                          DESCRIPTION OF PROBLEM:
No card number given!           As it says... ;-)
Unknown credit card number!     Not an AMEX/VISA/MC/DISC card ID number.
Invalid char. in card number!   An unallowable character entered in card
                                number. Only numbers 0-9  and dashes (-)
                                allowed.
Invalid ser. # length for x!    Invalid number of #'s  in the serial for
                                the specific credit card.

                                                SiGNeD:MHK

P.S. Hope you enjoy using this thingy...