Products:

$4.$ Class Product

This class is to keep track of information on different products that the pharmacy offers. This class supports the following information:

$$ ID: a unique identifier of the product

$$ name: the name of the product $($you can assume the product names are unique and they do not include any digit$)$

$$ price: the unit price of the product

$$ A method display$\_$info that prints the values of the Product attributes

$$ Extra attributes and methods if you want to define

Orders

$5.$ Class Order

This class is to store a customer's purchase information. This class supports the following

information of an order:

$$ customer: the one who makes the purchase $($can be a Basic or VIP customer$).$ You need to think$/$analyse carefully if this should be an ID$,$ name, or something else.

$$ product: the product of the purchase. You need to think$/$analyse carefully if this should be an ID$,$ name, or something else.

$$ quantity: the quantity of the product ordered by the customer

$$ A method compute$\_$cost that returns the original total cost $($the cost before the

discount$),$ the discount, the final total cost $($the cost after the discount$),$ and the reward. For example, if the original total cost of an order of the customer Tom $($VIP customer with reward rate of $100\%$ and discount rate of $8\%)$ is $30,$ then this method will return $(30,2\mathrm{.}4,27\mathrm{.}6,28).$

$$ Extra attributes and methods if you want to define.

Records

$6.$ Class Records

This class is the central data repository of your program. It supports the following information:

$$ a list of existing customers $$ you need to think what you should store in this list

$($customer ID$,$ customer name, or something else?$)$

$$ a list of existing products $$ you need to think about what you should store in this list

$($product ID$,$ product name, or something else?$)$

$$ This class has a method named read$\_$customers. This method takes in a file name and then read and add the customers in this file to the customer list of the class. In the sequel, we call this the customer file. See an example of the customer file below.

In this file, the customers are always in this format: customer$\_$ID$,$ customer$\_$name,

reward rate, discount$\_$rate $($if that is a VIP customer$),$ and reward. For example, in the

$1$st line, the customer$\_$ID is B$1,$ the name is James, the reward rate is $100\%,$ and the

reward point is $20.$ In the $3$rd line, the customer$\_$ID is V$3,$ the name is Tom, the reward

rate is $100\%,$ the discount rate is $8\%,$ and the reward point is $12.$ A Basic customer has an ID starting with the letter $"$B$"$ whilst a VIP customer has an ID starting with the letter $"$V$".$ The numbers in the ID after these characters $($B$,$ V$)$ are all unique $($i$.$e$.,1,2,3,5...$ are unique; for example, if there is a customer with the ID of B$1,$ there won't be a customer with the ID of V$1).$ In this part, you can assume there will be no error in this customer file $($e$.$g$.,$ the data format is always correct, and the reward and discount values are always valid$).$

$$ This class has another method named read$\_$products. This method takes in a file name and can read and add the products stored in that file to the product list of the class. In the sequel, we call this the product file. See an example of the product file below. In this file, the products are always in this format: product$\_$ID$,$ product$\_$name,

unit$\_$price. The product ID always starts with the letter $"$P$".$ The product IDs and names are all unique. You can assume there will be no error in this file $($e$.$g$.,$ the data format is always correct, and the values are always valid$).$

$$ This class also has two methods find$\_$customer and find$\_$product. These methods take in a search value $($can be either a name or an ID of a customer or product$),$ search through the list of customers$/$products and then return the corresponding

customer$/$product if found or return None if not found.

$$ This class also has two methods list$\_$customers and list$\_$products. These methods can display the information of existing customers and products on screen. The method list$\_$customers will display the customer ID$,$ name, the reward rate, the discount rate $($for VIP customers$),$ and the reward. The method list$\_$products will display the product ID$,$ product name, and the unit price. Note the two methods can be used to validate the reading from the two $.$txt files associated with the customers and products. NOTE you are allowed to add extra attributes and methods in this class if these attributes and methods make your program more efficient.

Operations

$7.$ Class Operations

This can be considered the main class of your program. It supports a menu with the following options:

i$.$ Make a purchase: this option allows users to make a purchase for a customer. Detailed

requirements for this option are below $($Requirements v$-$ix$).$

ii$.$ Display existing customers: this option can display all the information of all existing customers:

ID$,$ name, reward rate, discount rate $($only for VIP customers$),$ and reward.