Description
Assignment Overview
Before a game designer sits down to make a game, they always think – “But how can I make the
most money from my users, with the least amount of effort?” In this assignment, we won’t try to
make the game, but instead we’ll make the part of the game that really makes all the money –
Loot boxes!
What is a loot box?
Loot boxes are a way of selling items to users. Users will purchase a “loot
box” and opening the box provides a random item. Typically these boxes
produce one or more items, with some items being more rare than others.
Really, it’s quite similar to gambling and there is a lot of debate around if
they are ethical or not. I am not endorsing the use of loot boxes in games!
Note: You may be familiar with “gacha games”. These are more or less
the same concept. Feel free to theme accordingly!
We are going to make a text-based store to purchase loot boxes. There will be three tiers of loot
boxes: Common, Rare, and Epic. Each loot box will drop 3 items with different probabilities,
depending on the type of box. At the end, you will open the boxes and see what you get!
The Tools You’ll Use (These tools are not mandatory):
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
● We use loops any time we want to repeat an instruction multiple times
● We use while loops any time we want to loop until some event
● We use for loops when we know how many times we want to loop
● We can use the string function, .format(), to print nice strings (info in Tutorial 2!)
○ You can format a float to should two decimal places with {:.2f}
● We can import the random module to randomly generate loot from boxes
● We can use the string’s isdigit() function to check if a string is a positive integer before
trying to convert it
● \t can be used in a string to tab forward
Theme: Feel free to use any theme you would like! Give your game a name, interesting box
names, have fun with it. You are allowed to use the names I’ve provided here or change them
out. It can even be a game that exists, or based on another existing piece of media.
Marking: A marking scheme will be released shortly after the specification PDF goes live.
Check the submission page periodically for the uploading marking scheme.
Tips:
● Before trying to program anything, make sure to read the entire assignment, make sure
you fully understand what it is asking, and use flowcharts and pseudocode to help plan
your logic.
● Submit your solutions periodically to make sure that you’ll still get grades if something
goes wrong with your final submission.
● Always verify your submission after uploading it to make sure you submitted the correct
files
● Make use of office hours! The best way to receive help is to attend TA or instructor office
hours, or if that isn’t possible, seeking clarifications on the cuLearn forums. Always make
sure that the question hasn’t already been asked.
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
Problem 1: A Single Purchase
Submission: Save your file as a2q1.py and add it to the zip submission.
Goals: Learn how to use while loops to validate user input, make use of string formatting, and
perform simple math calculations.
This is the starting point for our text-based purchasing system for the game Raven Runner (pick
your own game if you’d like!). You will build the menu that allows the user to buy one or many of
a single type of loot box.
1. The program starts by asking for the player’s username
2. The program shows a menu to the user to purchase one of three loot boxes.
○ Display: The menu must display the number for the option, the rarity, the cost,
and the name of the box.
3. The user enters a number that corresponds with the loot box they would like to purchase
○ Invalid Inputs: The user is allowed to type incorrect inputs. If they do not type a
valid number, it should print an error message and show the menu again. You
can use a while loop to help with this.
4. The user is then asked how many of those loot boxes they would like to purchase
5. The user is given a personal message, thanking them for their business (using their
name), and a receipt is shown for their order.
○ Receipt Info: The receipt should show the loot box name, the number of boxes
they purchased, and the total cost of the purchase.
Example (user input is bold):
HELLO, GAMER! Welcome to the Raven Runner Loot Box Purchasing System.
First, what’s your player name? Connor
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
> 4
Error: That was not a valid selection. Please enter a number between 1-3
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
> Common
Error: That was not a valid selection. Please enter a number between 1-3
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
3. [Epic] The Three-Eyed Raven (7.99)
> 1
How many GeeGees ($1.50) would you like to purchase? 4
Thanks, Connor! Here is your receipt:
———————————
4x GeeGees ($1.50)
———————————
Total Cost: $6.00
Thank you! Good luck, gamer!
Important Notes:
● You an not ever assume the user will enter correct inputs
● Your output should be nicely formatted
Problem 2: Bulk Purchases
Submission: This should be a separate file from problem one, save to the file a2q2.py
Goals: Use multiple variables to track independent information, make use of while loops to
process until the user wants to quit, begin writing reusable code.
Firstly, copy your a2q1.py solution into a new file. The TAs will need both solutions. Save it as
a2q2.py.
In this problem, you will modify your previous solution so that we can purchase multiple loot
boxes at once.
1. Our menu will now need a “Complete Purchase” option to stop purchasing (you can
rename this, as long as it is clear)
2. Our menu will continue prompting for additional purchases until the selects the Complete
Purchase option
3. We will need to track how many of each type of loot box we are purchasing – one
variable per type
4. If the user selects the same box a second or third time, it should be added to the
previous amount
5. The receipt should contain a list of each box they have purchased; if they did not
purchase a type of box, it should not appear on the receipt
Tips: You will want variables for each type of box with information like the cost, the amount
you’ve purchased, and possibly even the name of the box. For clarity, try defining these
variables together and early in the program.
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
Tip: You can use global constant values to give names to the selections in your code! Example:
COMMON = 1
RARE = 2
EPIC = 3
QUIT = 4
Example:
HELLO, GAMER! Welcome to the Raven Runner Loot Box Purchasing System.
First, what’s your player name? Connor
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
4. Complete Purchase
> 1
How many GeeGees ($1.50) would you like to purchase? 2
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
4. Complete Purchase
> 2
How many Ravens ($3.00) would you like to purchase? 4
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
4. Complete Purchase
> 3
How many Three-Eyed Ravens ($7.99) would you like to purchase? 1
Please select a loot box from the menu below:
1. [Common] The GeeGee (1.50)
2. [Rare] The Raven (3.00)
3. [Epic] The Three-Eyed Raven (7.99)
4. Complete Purchase
> 4
Thanks, Connor! Here is your receipt:
———————————
1x GeeGees ($1.50)
4x Ravens ($3.00)
1x Three-Eyed Ravens ($7.99)
———————————
Total Cost: $22.99
Good luck, gamer!
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
Problem 3: Open Those Boxes
Submission: This should be a separate file from problem two, save to the file a2q3.py
Goals: Use nested for loops to repeat multi-step tasks a set number of times, understand how
to use cumulative probability in conditions
Firstly, copy your a2q2py solution into a new file. The TAs will need both solutions. Save it as
a2q3.py.
Now it’s time to open our boxes!
After the purchase is complete and the receipt is shown, we will use one for loop for each type
of box and open them. We will generate 3 items per box – use a nested for loop for this. Each
box will have different likelihoods of different boxes.
● A common box has an 80% chance to be common, 15% rare, 5% epic
● A rare box has a 50% chance of common, 40% rare, 10% epic
● An epic box has a 30% chance of common, 50% rare, 20% epic
When opening boxes, your program should:
1. For each box of one type…
a. For each of the three items to generate…
i. Generate a random number between 0 and 1.
ii. If it is less than or equal to the first probability (eg. 0.8), it’s a common
iii. Otherwise, if it is less than the first probability plus the second (eg.
0.8+0.15 = 0.95), it’s a rare
iv. Otherwise, it is an epic.
v. Let the user know which item they got.
Tips:
● For each type of box, you will need one for loop for each box of that type, and one for
loop for each item in that box
● You can use random.random() to get a float between 0 and 1
Bonus (2 marks): Write your box opening code as a function, named open_box()which
takes two parameters: The amount of boxes to open, and the type of box being opened. It does
not need to return anything. It should only contain the nested for loop for opening boxes
once. Use variables to determine the correct probabilities.
Example on Next Page
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
Example, starting from the receipt:
Thanks, ! Here is your receipt:
———————————
4x GeeGees ($1.50)
1x Ravens ($3.00)
4x Three-Eyed Ravens ($7.99)
———————————
Total Cost: $36.46
Good luck, gamer!
Time to Open Boxes!
————————
Opening common box 0
It’s a common item!
It’s a common item!
It’s a rare item!
Opening rare box 0
It’s a common item!
It’s a rare item!
It’s a rare item!
Opening epic box 0
It’s a rare item!
It’s an EPIC ITEM!
It’s a rare item!
Opening epic box 1
It’s a rare item!
It’s a common item!
It’s a rare item!
Opening epic box 2
It’s a common item!
It’s a common item!
It’s a common item!
Opening epic box 3
It’s a common item!
It’s a rare item!
It’s a rare item!
COMP 1405 C&D Fall 2020 Assignment 2 DUE: Tue. Oct. 20 @ 11:55PM EDT
Recap
Your zip file should contain your a2q1.py, a2q2.py and a2q3.py, files.
Submit your assignment2.zip file to cuLearn.
Make sure you download the zip after submitting and verify the file contents.
Late submissions will receive a 2.5%/hour deduction up to an 8 hour cut-off period
