Client/Server demo

Demonstrate in class that client/server is working.

For the bank, this means that you have a credit card processing
program written (a server), and that you can connect to it (using
sockets) and you can perform a transaction.  The transaction must
involve two-way data flow.  Generally it will be a request and a
response.

The bank is required to write a well-documented and working client
program.  The client must be able to submit a credit card number, a
dollar amount, and a transaction type, along with any other
information the bank may deem necessary.  The client must be able to
receive and properly interpret the response from the server, including
options such as "card denied," "transaction completed," etc.

For all other companies, nothing is due until the bank has their
client and server working properly and has demonstrated it in class.
(If that never happens, you will get full credit for the assignment
even though you never did it.  But don't count on that.  The bank will
come through.)

Once the bank has credit card processing working, the bank will give
to each other company a copy of the bank's working client (not
server).  Your task is to build a client appropriate to your own
needs, and to make sure that it cooperates with the bank's server.
You can do this by simply modifying the bank's client that they gave
you.

The bank will be graded on whether its client and server work together
properly, and how clearly documented the client is.  Everyone else
will be graded on whether their client works with the bank's server.