COSC1076 | Semester 1 2023
Advanced Programming Techniques
Assignment 2 Vending Machine
Assessment Type: Both group and individual assessments.
Weight: 40% of the final course mark
Due Date: 23:59, Friday 26 May 2023 (Note that there is also a group demonstration due in Week 10)
Silence Policy: From 5:00pm, Thursday 25 May 2023 (Week 12)
Submission: Online via Canvas. Submission instructions are provided on Canvas.
1 Introduction
1.1 Overview
In this assignment, you will use your C++ programming skills to create a front-end system for a vending
machine. The vending machine serves all kinds of pastry treats. The company’s name is Penelope’s Pastry
Delights and as such, the executable you are creating will be called “ppd”.
The following sections contain the details of this assignment. You are expected to understand every requirement
explained in this document and implement all of them accordingly. This assignment has a strong emphasis on
linked lists. You should get yourself familiar with this concept as soon as possible.
In this assignment you will:
• Practice the programming skills covered throughout this course, such as:
– ADTs
– Linked Lists
– Pointers
– Dynamic Memory Management
– File Processing
– Program State Management
– Exception Handling
• Practice the use of testing
• Implement a medium size C++ program:
– Use features of C++14
– Use elements of the C++ STL
• Work as a team
– Use group collaboration tools
This assignment is divided into four Milestones:
• Milestone 1 (Group work): Test Cases, to be developed to ensure your ppd program implementation is
correct (due week 10).
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• Milestone 2 (Group work): A fully functioning implementation of the base ppd program, which pass
Milestone 1 tests. The group work (milestone 1 & 2) is worth 25% of the course mark. Your group is
required to demonstrate REQ5, 6, 8 and 9 in week 10 lab session (due week 10).
• Milestone 3 (Individual work): You will individually extend upon your group’s implementation with
additional functionality (called enhancements). The individual work is worth 15% of the course mark
(due week 12).
• Milestone 4 (Group + Individual work): Written report (no more than 4 pages) analysing the design and
implementation of your software, and the use of your test cases. You will demonstrate your group and
individual work. This is where your final work will be graded (due week 12).
Group Progress Update (Group work): Your group will need to provide regular updates on your progress
in this assignment to your tutor during your weekly lab classes. This will require your group to have completed
a list of activities. Group Progress Update will not be marked directly, however, this will influence the final
grade.
1.2 Group Work
The group work must be completed in groups of 4.
• You may form groups with any student in the course.
• We strongly recommend that you form groups from within your labs, because:
– Your tutor will help you form groups, but only within your lab.
– You will have plenty of opportunity to discuss your groups progress and get help from your tutor
during the rest of the course. It will be extremely helpful for your whole group to be present, but
this can’t happen if you have group members outside the lab.
– If you form a group with students from multiple practicals, you will still need to be allocated to a
single tutor and we may need you to switch labs to ensure everyone gets a fair amount of time.
Groups for Assignment 2 must be registered with your tutor by week 8 lab. Your tutor will “register”
your group on Canvas. If you are unable to find a group, discuss this with your tutor as soon as possible.
If at any point you have problems working with your group, inform your tutor immediately, so that issues may
be resolved. We will do our best to help manage group issues, so that everybody receives a fair grade for their
contributions. To help with managing your group work we will be requiring your group to use particular tools.
These are detailed in Section 5.
There are important requirements about keeping your tutor informed if you have been unwell or other wise
unable to contribute to your group. Remember your actions affect everybody in your group.
1.3 Learning Outcomes
This assessment relates to all of the learning outcomes of the course which are:
• Analyse and Solve computing problems; Design and Develop suitable algorithmic solutions using software
concepts and skills both (a) introduced in this course, and (b) taught in pre-requisite courses; Implement
and Code the algorithmic solutions in the C++ programming language.
• Discuss and Analyse software design and development strategies; Make and Justify choices in software
design and development; Explore underpinning concepts as related to both theoretical and practical
applications of software design and development using advanced programming techniques.
• Discuss, Analyse, and Use appropriate strategies to develop error-free software including static code analysis, modern debugging skills and practices, and C++ debugging tools.
• Implement small to medium software programs of varying complexity; Demonstrate and Adhere to good
programming style, and modern standards and practices; Appropriately Use typical features of the C++
language include basic language constructs, abstract data types, encapsulation and polymorphism, dynamic memory management, dynamic data structures, file management, and managing large projects
containing multiple source files; Adhere to the C++14 ISO language features.
• Demonstrate and Adhere to the standards and practice of Professionalism and Ethics, such as described
in the ACS Core Body of Knowledge (CBOK) for ICT Professionals.
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2 Description of the Program and Functionalities
You have been approached by a company to create a front-end system for a vending machine written in C++.
The vending machine serves all kinds of pastry treats. The company’s name is Penelope’s Pastry Delights
and as such, the executable you are creating will be called “ppd”. In this assignment you are to implement an
application that will perform the above tasks as a single user model.
This section describes in detail all functional requirements of this assignment. You should make a conscientious
effort to write your program in a way that is capable of replicating the functionalities of the ppd program,
described in the requirements below.
REQ1: Command-line arguments
A user of your program must be able to execute it by passing in the names of two data files that the system is
to use. You need to check that exactly 3 command line arguments are entered. Your program will be run using
these command line arguments:
[s3344949@csitprdap02]$ ./ppd
For example:
[s3344949@csitprdap02]$ ./ppd stock.dat coins.dat
REQ2: Load Data
Your program needs to be populated with the data provided in the 2 data files whose names are conveyed
via the command line. You will need to tokenize this data in order to load it into the system. You may use
the class definitions provided in the startup code to store your system data. As part of this requirement you
need to ensure that the specified files are valid (that is, they exist and the data contained in them matches the
specification for this assignment). You need to abort the program and provide a suitable error message if this
is not the case.
Item (or stock) File Format:
[ItemID]|[ItemName]|[ItemDesc]|[Price]|[NumberOnHand]
Please note that the Price is stored as numbers delimited by the ‘.’. The number to the left of the ‘.’ is the
dollars and the number to the right will be the cents, for example:
I0001|Meat Pie|Yummy Beef in Gravy surrounded by pastry|3.50|50
Where the 3 represents the dollar component and the 50 represents the cents component of the price. A missing
‘.’ from the price should be considered a data error.
You must ensure that items are inserted in the linked list sorted by name.
Money data file format:
[denomination],[quantity]
That is, there will be a row for each value of money that exists and the system will have an amount of each
denomination. For example:
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1000,3
500,4
200,20
100,30
50,5
20,3
10,40
5,20
This means that the system currently has 3 x 10 dollar notes, 4 x 5 dollar notes, 20 x 2 dollar coins, etc. Note
that the above denominations are the only valid denominations for your vending machine. The vending machine
does not accept $20 or $50 notes. A valid file will always contain exactly 8 denominations, with no repeated
denominations. If you wanted to initialise the vending machine with no change then the valid way to do that
would be:
1000,0
500,0
200,0
100,0
50,0
20,0
10,0
5,0
Please note that you cannot assume that the data contained in these files are valid. Some examples (this is not
a complete list) might be, there may be lines with too many or too few fields, and the data in each field may
not be of the correct type, range and/or length.
Sample (valid) data files have been provided with the startup code. Make sure that your program works with
at least these files. We will also be testing your program with invalid data in the data files. We recommend
that you get your program working for the (valid) provided data files first. Then spend some time testing for
invalid files after you have completed most/all of the remainder of the assignment.
You should validate the contents of the files when loading. Please note that we may feed in file names when
testing that don’t end in ’.dat’, so please don’t validate for that. Likewise, you cannot assume the data files
will be in the same directory as the executable, nor that we will have the same directory structure as you.
REQ3: Display Main Menu
Your program must display an interactive menu displaying 9 options. Your menu should look like this:
Main Menu:
1.Display Items
2.Purchase Items
3.Save and Exit
Administrator-Only Menu:
4.Add Item
5.Remove Item
6.Display Coins
7.Reset Stock
8.Reset Coins
9.Abort Program
Select your option (1-9):
Your program must print out the above options and then allow the user to select these options by typing the
number and hitting enter. Upon selection of an option, an appropriate task will be carried out.
Upon completion of all options except “Exit”, the user is returned to the main menu. You can assume that
customers can only see the first three menu options, and the administrator can see all of them.
The behavior of these menu options is described in following requirements from REQ4 to REQ12.
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REQ4: Display Items
This option allows the user to request a display of the items available for purchase. This is the data loaded into
the linked list in the REQ2. This requirement should behave as follows from the main menu, the user selects 1
and data should be displayed in the following format:
Items Menu
----------
ID |Name | Available | Price
-------------------------------------------------------------------
I0002|Apple Pie |18 |$ 3.00
I0003|Lemon Cheesecake |20 |$ 4.00
I0004|Lemon Meringue Pie |20 |$ 3.00
I0005|Lemon Tart |20 |$ 3.75
I0001|Meat Pie |18 |$ 3.50
REQ5: Purchase Item
This option allows the user to purchase an item from the menu. This function is called from the main menu
when the user has finally decided to purchase an item. This function allows the user to pay for their item by
collecting money from them, and adjusting balances within the system as appropriate. Change is then given
back to the customer, if appropriate. The number of items on hand should also be deducted. You should not
allow an item to be purchased if there are 0 or less of that item on hand. For example, from the main menu, if
the user selects 2, then the following should be displayed:
Select your option (1-9): 2
Purchase Item
-------------
Please enter the id of the item you wish to purchase:
If the user enters the item ID I0001, and subsequently $2, $3 and $5 as prompted, then the following should
be displayed:
You have selected "Meat Pie - Yummy Beef in ... by pastry". This will cost you $ 3.50.
Please hand over the money - type in the value of each note/coin in cents.
Press enter or ctrl-d on a new line to cancel this purchase:
You still need to give us $3.50: 200
You still need to give us $1.50: 300
Error: $3.00 is not a valid denomination of money. Please try again.
You still need to give us $1.50: 500
Here is your Meat Pie and your change of $ 3.50: $2 $1 50c
After which the user would be returned to the main menu.
When refunding money, you must display each note or coin separately used in the refund and you must ensure
that prior to the sale that there is sufficient denominations in the system so that the customer is given the
correct change. You must also subtract these coins from the coins array if a sale can take place. Note that coins
entered to pay for an item can form part of the change that is given to the customer if that is required to give
the customer the smallest amount of change possible. If ppd cannot give correct change then the sale should
not occur, and your program should display an appropriate message explaining why.
If the user presses enter on a new line, refund all the coins/notes they have entered so far and return them to
the main menu. If Ctrl-d is entered, then exit the program.
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REQ6: Save and Exit
You must save all data to the data files that were provided on the command line when the program loaded up.
When the saving is completed, you must have the program exit. The specifications mentioned for each file must
be maintained and the program must be able to load up your files as easily as it loaded up the files that we
have provided you with. Also, at this point, once you have implemented dynamic memory allocation, you must
free all memory allocated and exit the program. A program which does everything but exit the program will
still lose marks, as much as a program that does not implement any other requirement.
REQ7: Add Item
This option adds an item to the system. When the user selects this option, the system should generate the
next available item id and associate that with this item. The user should then be prompted for the Name,
Description and Price (a valid amount of money in dollars and cents). The item should then be allocated the
default “on hand” value specified in the startup code. The new item id shall have an ‘I’ prepended to it and
will be 5 characters long. For example:
The id of the new stock will be: I0006
Enter the item name: Baklava
Enter the item description: rich, sweet pastry made of layers of filo filled with chopped
nuts and sweetened and held together with syrup or honey.
Enter the price for the item: 8.00
This item "Baklava - rich, sweet pastry made of layers of filo filled with chopped nuts
and sweetened and held together with syrup or honey." has now been added to the menu.
Please note that the price entered for an item must have a dollars and a cents component as above.
REQ8: Remove Item
Remove an item from a category and delete it from the system, including free memory that is no longer being
used. For example,
Enter the item id of the item to remove from the menu: I0001
"I0001 - Meat Pie - Yummy Beef in Gravy surrounded by pastry" has been removed from the
system.
REQ9: Reset Stock Count
This option will require you to iterate over every stock in the list and set its ‘on hand’ count to the default
value specified in the startup code. You should display a message once this is done such as
“All stock has been reset to the default level of X”
where X is the default stock level specified in the startup code.
REQ10: Reset Coin Count
This option will require you to iterate over every coin in the coin list and set its ‘count’ to the default value
specified in the startup code. You should display a message once this is done such as
“All coins have been reset to the default level of X”
where X is the default amount of coins specified in the startup code.
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REQ11: Display Coins
This option will require you to display the coins as follows. In particular, the counts of coins should be correctly
aligned, and they should be sorted from lowest to highest value:
Coins Summary
-------------
Denomination | Count
---------------------------
5 Cents | 20
10 Cents | 40
20 Cents | 3
50 Cents | 1
1 Dollar | 28
2 Dollar | 16
5 Dollar | 2
10 Dollar | 5
REQ12: “Abort”
This option should terminate your program. All program data will be lost. You should also be freeing memory
at this point as well.
REQ13: Return to Menu Functionality
Your program should allow the user to return to the main menu at any point during these options. The user
can do this by hitting enter on an empty line. If the user is in the middle of a transaction, that transaction
should be cancelled, and money refunded.
REQ14: Memory Leaks and Abuses
The startup code requires the use of dynamic memory allocation. Therefore, you will need to check that your
program does not contain memory leaks. Use the following:
valgrind –-leak-check=full –-show-leak-kinds=all
to check for memory leaks. Marks will only be awarded for this requirement if the feedback valgrind provides
reports zero memory leaks and no other memory related problems.
Another common problem in is memory abuses. These are inappropriate accesses such as reading from uninitialized memory, writing to memory addresses you should not have access to and conditional statements (if,
while, etc) that depend on uninitialized memory. You can test for these again by using valgrind:
valgrind –-track-origins=yes
Sample Executable
An executable of the program with most of the above-mentioned functionalities is provided. You can access
and run the sample executable file directly on the school teaching server (e.g., via PuTTy on Windows) at the
following location: ∼/KDrive/SEH/SCSIT/Students/Courses/COSC1076/apt/ppd. Once logged in with your
RMIT credential, you can just cd into this folder, and follow the readme.txt file to run the executable file ppd.
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3 Deliverables
3.1 Mandatory Requirements
As part of your implementation, you must:
• Implement your own Linked List.
• Use your Linked List implementation to store the items for ppd.
• You may only use the C++14 standard library. You may not incorporate any additional libraries.
If you fail to comply with these mandatory requirements, marks will be deducted.
3.2 Milestone 1: Test Cases (Group Component)
For Milestone 1, you must develop test cases for your ppd implementation, including your enhancements. These
test cases will help ensure that your ppd implementation is correct.
For a single test case, following 3 files need to be provided:
1. .input - Input to provide to the ppd program via stdin.
2. .output - Expected output from the ppd program on stdout.
3. .expcoins - Expected output saved coin file when exiting ppd program.
Likewise if you have tests for the stock file, follow the above naming convention for your tests.
A test is run using the following sequence of commands.
./ppd stock.dat coins.dat < .input > .actual_ppd_out
diff -w .output .actual_ppd_out
diff -w -y .expcoins
If the first diff command displays any output, then the test has failed. This command checks to see if two files
have any differences. The -w options ignores any white-space.
The second diff command checks if two coin files (expected vs actual) have any differences.
You should aim with your tests to thoroughly test all the functionality of your program. If you write insufficient
tests, your program may fail our tests when we assess you.
3.3 Milestone 2: Basic ppd Implementation (Group Component)
For Milestone 2, your group must implemented the base ppd program as described in Section 2. Section 2 lists
the components that your group must implement. Generally, it is up to your group to decide the best way to
implement these components. However, there are some important requirements that your group must satisfy.
!
Aspects of this specification are flexible and open to your interpretation. It is up to your group to
determine the best course of action. You will need to analyse and justify your choices in the report.
Your group will also need to consider the data structures that are used to represent aspects of ppd, and
functionality. It is up to your group to make this decision provided that you meet the requirements in Section
3.1. In your report your group will be marked on your analysis of the above choices.
Finally, remember to do the the group contribution spreadsheet described in 5.3 - fill this in on a weekly basis
so it is accurate.
3.3.1 Group Demonstration
Your group is required to attend an assignment demonstration in Week 10 lab session. Your group
will be required to demonstrate REQ5, 6, 8 and 9 in this demonstration using test cases you developed from
Milestone 1. Please note that this includes implementation of any requirements that these options depend upon.
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Each presentation should be around 12 minutes (for a group of 4), with an emphasis on showing what the group
has done collectively as a team, as well as contribution from each individual to the project so far. Group work
will be evaluated (see Section 8), and poor group work may result in mark deduction for individuals in the team
(Section 7.3). You should also be ready to answer any additional questions about design and implementation
from your tutor.
3.3.2 Group code and Test Cases
The deadline for submitting your group’s Milestone 1 (test cases) and Milestone 2 (code for the ppd base
implementation) is the end of Week 10 (11.59pm, Friday 12 May 2023 (Week 10)). See detailed information
regarding submission instructions on Canvas.
3.4 Milestone 3: Enhancements (Individual Component)
In Milestone 3, as an individual you will make significant expansion(s) to the functionality of your group’s ppd
program. This milestone is your opportunity to showcase to us your skills, capabilities and knowledge! You
will select your enhancements from the provided options in Section 4. Additionally, if you group’s Milestone 2
solution has significant errors or is significantly incomplete, please read Section 4.3.
Milestone 3 is relatively open-ended. You are given some directives, however, there is a lot of room for you
to make considered choices. However, this showcase of your skills is not just about “making the code work”.
A major focus is on how you choose to implement an enhancement, and the justifications of the reasons why
you chose a given data structure, class hierarchy, language feature, or algorithm to name a few examples.
Enhancements are classified as minor or major. Enhancements must be substantially functional to get marks.
To get a higher grade you will need to implement one or more minor or major enhancements. This is described
in the marking rubric.
3.4.1 Configurable Enhancements
Where reasonably possible, your enhancements should be configurable. That is, it should be possible to enable (or disable) each enhancement at run-time (not through compilation). In particular, this means your
enhancements can be “turned-off” so that your program runs the same as Milestone 2 (verbatim).
3.4.2 Changes to Saved Stock file
Some enhancements may require you to modify the format of the saved-stock file. However, it is recommended
that your program with enhancements still support loading stocks from the default saved-stock format used in
Milestone 2.
To distinguish your new saved-stock format from the “default” Milestone 2 format, we recommend adding a
special code at the start of your new saved-stock format, such as:
#myformat
...
In addition, you can use a different file extension to further distinguish the new saved stock file, e.g., instead of
using .dat, you can save the file using .sav as the extension.
3.5 Milestone 4: Written report (Group + Individual Component)
3.5.1 Written report
Your group must write a report, that analyses what your group has done in this assignment. Additionally, each
individual must write a short report that analyses their individual enhancement(s). The group should combine
the group report and the individual report and one group member should submit it via Canvas. The combined
report is due at the same time as the individual submission (11.59pm, Friday 26 May 2023 (Week 12)).
• The report should be A4, 11pt font, 2cm margins and single-space.
• The section of the report describing the group’s work must be no more than 4 pages.
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• Each individual must add 1 additional page about their enhancements.
• Thus the final report must not exceed 8 pages for a group of four.
• Only the first 4 pages (group), and 1 page (individual) will be marked.
• Modifying fonts and spacing will count as over length.
• Figures, Tables and References count towards these page limits.
In this assignment, you are marked on the analysis and justification of the choices you have made. Your report
will be used (in conjunction with the demonstration) to determine the quality of your decisions and analysis.
Good analysis provides factual statements with evidence and explanations. Statements such as:
“We did because we felt that it was good” or “Feature is more efficient”
do not have any analysis. These are unjustified opinions. Instead, you should aim for:
“We did because it is more efficient. It is more efficient because . . . ”
We are asking for a combined report as it keeps the context of each individual’s enhancements with the whole
group’s original implementation.
3.5.2 Group Component of the Report
In the group section of your report, you should discuss aspects such as:
• Your group’s use of at least one linked list, and the reasons for where the linked list is used.
• Your group’s choices of ADTs, and how these leads to a “well designed” program.
• The efficiency of your implementation, such as the efficiency of your use of data structures.
• The reason for each of your tests.
• Your group co-ordination and management.
3.5.3 Individual Component of the Report
In the individual section of your report, you should discuss aspects such as:
• The design of your enhancements, including any changes (and additions) to the data structures and ADTs
you had to make when enhancing your group’s implementation.
• The efficiency of your enhancements, such as the efficiency of your use of data structures.
• Limitations and issues that you encountered with your group’s implementation.
4 Suggested Enhancements for Milestone 3
4.1 Minor enhancements
Minor enhancements are smaller in scope, and require only a small modification to your software design.
4.1.1 Help!
Whenever there is a user prompt, the user may type “help” and the program should display some text to help
the user determine what they commands they may execute.
4.1.2 Better Invalid Input
Whenever the user enters invalid input at the user prompt, the program should show a useful error message to
explain why the input was invalid.
4.1.3 Colour
Use colour to display (or highlight) the dollar amount that needs to be paid by the user. The Linux, Mac (and
most similar) terminals support the use of colour through the use of escape codes. A simple internet search will
show you tutorials for working with escape codes.
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4.1.4 Popular Items
The program maintains a list of items that have been most frequently purchased by any user who has used your
vending machine of ppd. You will need to devise a way to save, load, and display this list.
4.2 Major enhancements
Major enhancements are large in scope, and require significant modifications to your software design.
4.2.1 2-dimensional linked-list
Penelope’s Pastry Delights sells different types of “Meat Pie”, e.g., “Steak & Cheese”, “Chicken & Mushroom”,
“Steak & Onion”, and “Spanish & Feta” etc 1
. You can implement a 2nd linked-list to store information about
these “item options" for each item. For example, there could be also different kinds of coffee for the “Coffee”
item on your linked-list as well, such as “Latte”, “Cappuccino”, and “Espresso”, etc 2
.
This means you need to implement a 2-dimensional linked-list, where we can first traverse on the item list, and
then for each item, we can also traverse along a sub-list of item options. When displaying all items, then items
on the item list as well as the sub-list should be all displayed.
4.2.2 Doubly-linked list
Re-implement your singly-linked-list for your ppd into a doubly-linked list, where you can navigate either in
forward or backward direction on the list. In fact, you can start traversing the list from either the start or the
end of the list now. Your functionalities for ppd as described in Section 2 should remain the same. For your
implementation, you need to demonstrate that for both “inserting” and “removing” items functionalities, your
doubly-linked list should be functional accordingly.
4.2.3 Reimplement the main menu using the Command design pattern
Design patterns are examples of common solutions to a problem that have been distilled into recommended
approaches. With this extension you will use the Command pattern which is an object-oriented approach that
uses inheritance to model menu items with text and a callable function. Please see this webpage:
https://refactoring.guru/design-patterns/command
for a further explanation. Please note that while the example provided uses the idea of ‘buttons’, it can just as
easily be applied to menu items.
4.3 Milestone 2 Code with Significant Errors
This section is a general statement. This is provided as a starting point from which to approach your tutor.
This option may only be used if you have discussed the matter with your tutor.
It is possible that your group’s ppd program may contain errors. If the errors in the your group’s ppd program
are small, while you should fix these in your individual work, they are not considered a significant change.
However, if your group’s ppd program has significant errors or is missing significant functionality, then you may
be able to negotiate with your tutor to fix these error as a minor enhancement. As each group’s program
is different, this will be determined on a case-by-case basis.
Please note that this does not excuse you from failing to make sufficient contributions to your group. While you
may be able to “make-up” some functionality in this milestone, you should not use this as an excuse to make
an insufficient contribution.
1Top 10 most popular Australian meat pies: https://gdaygourmet.com/top-10-most-popular-australian-meat-pies/
2Types of coffee explained: https://www.nescafe.com/in/coffee-types
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5 Managing Group Work
This group assignment can be conducted entirely online, without you ever meeting your group members faceto-face. This isn’t a problem, with the available online tools. The challenge for you will be using these tools
effectively. You will need to make extra efforts and be very dedicated and diligent in working with your
team members. This will include setting up dedicated times for meetings and group programming sessions.
5.1 Group Work Tools
To help manage your group work, and demonstrate that you are consistently contributing to your group, we
are going to require you to use a set of tools. Please note that if you do not use the