Function Procedure
===

I have to create an order form for a company. On the left hand side the customer enters his name, address, and the items bought. The right hand side has a list box with the invoice displayed. The I need help with the following:

1.The invoice number consists of the capitalized first two letters of the customer’s last name, followed by the last four digits of the zip code. 

2.The customer name is input with the last name first, followed by a comma, a space, and the first name. 

3.However, the name is displayed in the invoice in the proper order.

4.The generation of the invoice number and the reordering of the first and last names should be carried out by Function procedures.