COMP$216$ Networking for Software Developers

Lab $3$ Shopper Class $(40$ Marks$)$

This is an individual lab. Using a Visual Studio Code to write the python statement to define a

Shopper class. The test harness is provided to you by the instructor as well as the resulting output

given.

Description of the Shopper Class

Class variable

There are six class variables i$.$e$.$ variables that are shared by all objects of this class

$\_\_$prices

This is a python dict that contains the grocery items as well as their unit price. This is defined as

follows:

$\_\_$prices $=\{$ 'apple': $1\mathrm{.}8,$ 'bread': $2\mathrm{.}2,$ 'milk': $4\mathrm{.}9,$ 'pepper': $1\mathrm{.}2\}$

$\_\_$sale$\_$items

This is a list that contains all the items that are on sale in this period. A discount of $15\%$ is applied

to the price of each item in this collection. This is defined as follows:

$\_\_$sale$\_$items $=$ 'apple banana'.split$()$

Four other class variable that are define as follows:

$\_\_$discount$\_$threshold $=6$

When the total cost of a purchase exceeds this amount then a discount is applied to the cost

$\_\_$default$\_$price $=2\mathrm{.}50$

If an item is not found in the $\_\_$prices dictionary, then this will be the default price

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$\_\_$volume$\_$discount $=0\mathrm{.}9$

This is the rate of discount when the total cost exceeds the discount$\_$threshold

$\_\_$sales$\_$discount $=0\mathrm{.}85$

This is the rate of discount on an item if this item is in the $\_\_$sales$\_$time list.

Constructor

The constructor takes two argument that represents the name of the shopper and the amount of

money she has. It assigns the argument to appropriate instance variable. It also creates an empty

list to store the purchases.

Each purchase is a single tuple comprising of the name of the item and the price actually paid for

the item.

Instance property

There is a single instance property that returns the name of this shopper object

Class method

There are three class methods:

$1.$ One that returns the price list.

$2.$ One that returns the list of sale items.

$3.$ One that adds a new item to the sale items list.

Instance method

There are two instance methods:

purchase

This method takes a list of items to be purchase. It calculates the total price of the purchase by

processing each item in the argument as show below:

The price of an item is obtained from the price list. If it is not found in the price list then the

default price is used. $[$How to determine if an item in not in the dict$]$

If the item is in the sales list then a discount is applied to the price

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The item as well as the result price is added to the list as a tuple. $[$How to create a tuple with

name and price and how to add the tuple to the list$]$

When all the items are processed, if the final cost is over the credit threshold, then a

discount is applied to this amount and then subtracted from the amount of money this

object has left over.

$\_\_$str$\_\_$

This method returns a string representing this object i$.$e$.$ the name, cash and all its purchases

pertaining to this shopper.

How to do this assignment.

From the above description and test harness and the result output below, try to deduce the

definition of the Shopper class. Code this class in visual studio code and copy the test harness

below. Execute the code and ensure that the output matches EXACTLY with the output on the

following page.

You must use python f$-$strings for your output.

Documentation.

Because the code is so simple no code documentation is required, however you must put

following information including name, student ID$,$ course number and the current date at the top

of your code.

Lab $3$: Shopper Class

Name: FirstName LastName

Student ID: $123-456-789$

Course: COMP$216-008$

Date: January $25,2024$

How to submit this assignment.

Submit COMP$216\_008\_$Lab$3\_$FirstLastName.py to the course dropbox.

$$ Due Date: $4$pm$,$ February $1,2024$

$50\%$ penalty for late submission before $10$am February $6,2024.$

$$ No acceptance after $10$am February $6,2024.$

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Test Harness

You may not change the test harness.

print$($f$\text{'}$Price dict: $\{$Shopper$.$price$\_$list$()\}\text{'})$

print$($f$\text{'}$Sales list: $\{$Shopper$.$sale$\_$items$()\}\text{'})$

tom $=$ Shopper$(\text{'}$Tommy$\text{'},20)$ #create a shopper object

print$($f$\text{'}$

$\{$tom$\}\text{'})$ #display the object

items $=$ 'bread milk apple'.split$()$ #list of items to buy

print$($f$\text{'}$

$\{$tom$.$name$\}$ is purchasing: $\{$items$\}\text{'})$

tom.purchase$($items$)$ #volume discount

print$($f$\text{'}\{$tom$\}\text{'})$ #display the object

dave $=$ Shopper$(\text{'}$Dave$\text{'},25)$ #new shopper

items $=$ 'banana milk'.split$()$ #one sale item

print$($f$\text{'}$

$\{$dave$.$name$\}$ is purchasing: $\{$items$\}\text{'})$

dave.purchase$($items$)$

print$($f$\text{'}\{$dave$\}\text{'})$ #display the object

Shopper.add$\_$sale$\_$item$(\text{'}$pepper$\text{'})$ #add pepper to the sales items list

COMP$216$ Networking for Software Developers Classes Week$3\_$Lab$3$

Winter $2024$