CT$701$ Programming Fundamentals

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Assignment $2$ Supermarket Self$-$Service Checkout

This assignment will test your skills in designing and programming applications to specification and is worth

$30\%$ of your marks for this course. This is an INDIVIDUAL ASSIGNMENT $$ and while you may discuss it with

your fellow students, you must not share designs or code or you will be in breach of the university

plagiarism rules. This assignment should take you approximately $20$ hours to complete.

Assignment Overview

You are tasked with creating a text$-$based program for simulating a supermarket self$-$service checkout using

the Python $3$ programming language.

The assignment is broken up into two main

components:

$1.)$ Design and model two classes: Product

and CheckoutRegister,

$2.)$ Create a computer program that allows

a user to interactively check out a

number of products, then provides an

opportunity to enter some virtual money to pay for the products and finally and prints out a receipt for

the user $($to the screen, not on paper$),$ and finally

Your submission should consist of one Microsoft Word or LibreOffice document containing the first part of the

assignment, and three Python scripts that implement the computer program $($checkoutregister$.$py$,$

product.py and main.py$).$

The main.py script runs the main logic of the program and will use instances of the CheckoutRegister and

Product classes to simulate checking out of the supermarket.

Towards the end of this document you will also be provided with the output of a simulated run of the completed

computer program which may help you with this assignment.

Assignment Part $1$ Details $$ Class Design

Think of a product that you can buy from a supermarket, like maybe a can of soup or an apple.

Start by listing all the properties of that object that you can think of $$ try to come up with at least ten general

properties of a Product and write these down in your Assignment$\_$Part$\_1\_$ Microsoft

Word document.

Next, use the process of abstraction to cut the number of properties back to only four $$key$$ properties $$ write

these down in the next section of your Word document.

Now, fill in the class diagram for your Product class in the Word document. Your product class does not have

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to have any methods $($i$.$e$.$ functions$)$ associated with it to perform any actions other than a constructor which

takes and set the four key properties that you$$ve identified.

Next we$$ll move on to CheckoutRegister class $$ think about what information the checkout has to keep track

of to allow you to successfully check out of the supermarket. There will only really be three key properties that

the CheckoutRegister cares about, and the CheckoutRegister class should have the following four methods

available:

$1)$ A default constructor that takes no arguments and initialises a new object and its properties,

$2)$ accept$\_$payment$($some$\_$amount$),$

$3)$ scan$\_$item$($some$\_$product$),$ and

$4)$ print$\_$receipt$().$

Fill in the class diagram for the CheckoutRegister class in the Word template, and that$$sthe first part completed!

Assignment Part $2$ Details $$ Software Implementation

You are free to implement the software however you see fit, however the functionality of the software should

be able to match the following output. Note that in the below run of the program I have $$hard$-$coded$$ a small

number of Product instancesso that products exist which can they can be checked out $$ in your code you should

do the same.

Your program does not have to have the facility to add new products $$ just define a few and use them as

demonstrated below. If the final option of $($N$)$ext customer is chosen, the program should run again

Example Program Output

$-----$ Welcome to X$-$mart checkout! $-----$

Please enter the barcode of your item: $123$

Milk, $2$ Litres $-$ $$2\mathrm{.}0$

Would you like to scan another product? $($Y$/$N$)$ y

Please enter the barcode of your item: $456$

Bread $-$ $$3\mathrm{.}5$

Would you like to scan another product? $($Y$/$N$)$ y

Please enter the barcode of your item: $999$

This product does not exist in our inventory.

Would you like to scan another product? $($Y$/$N$)$ n

Payment due: $$5\mathrm{.}5.$ Please enter an amount to pay: $5$

Payment due: $$0\mathrm{.}5.$ Please enter an amount to pay: $-3$

We don't accept negative money!

Payment due: $$0\mathrm{.}5.$ Please enter an amount to pay: $2$

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$-----$ Final Receipt $-----$

Milk, $2$ Litres $$2\mathrm{.}0$

Bread $$3\mathrm{.}5$

Total amount due: $$5\mathrm{.}5$

Amount received: $$7\mathrm{.}0$

Change given: $$1\mathrm{.}5$

Thank you for shopping at X$-$mart!

$($N$)$ext customer, or $($Q$)$uit$?$ q

$>>>$

Submission and Marking Process

You must supply your program source code files and your document containing the class design and test

cases.

Assignments will be marked on the basis of fulfilment of the requirements and the quality of the work. In

addition to the marking criteria, marks may be deducted for failure to comply with the assignment

requir