CSCA20 - Lab 4
Selection
Learning Objectives
This lab focuses on selection, building up your skills with using if statements, and also combining
them with loops to build more interesting/powerful tools.
Prelab
We’ve provided you with some starter code that prints a menu and asks the user to choose an
option. Before your tutorial, you should get this code running, and write code that will print the
action needed based on that input (e.g., if the user chose T, it should print Calculating total)
Demonstration & Evaluation
Successfully completing this lab will demonstrate competency in User Input/Output, Variables,
and Selection. There will also be an opportunity to demonstrate mastery in user Input/Output.
You do not need to complete the mastery portion to demonstrate competency in the other areas.
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The Scenario
The Union for Tracking Seaborn Contaminants (UTSC) has asked you to build a tool to track
the number of kilograms of plastic their ocean cleanup rigs clean on a daily basis 1. They want to
be able to add the kilograms cleaned each day, calculate the total amount removed over certain
time periods, and the number of days that their rigs were pushed beyond their approved limits by
collecting too much plastic.
Menu
The starter code presents a simple menu that gives the user options for entering data, retrieving
information, or quitting.
If the user enters any other letter, the code should say invalid input: please try again
and present the menu again.
Adding Data
Your code should prompt the user with the date and ask for input. e.g., Enter kg of plastic
removed on day 17:
Calculating Totals
Your code should prompt the user to select A for the total removed in all days entered, or R for
the total removed in a range of days. If the user chooses R, they should then be prompted for the
start and end dates of that range. The user should then be presented with the total kg removed
during the specified time.
Calculating Overload Days
Your code should prompt the user to select A for all overload days, or R for overload days within
a range of days. Then the user should be prompted for the threshold (max kg rigs are meant to
collect) and then be presented with the total number of days where the collected amount exceeded
the threshold during the specified time.
Mastery
You can demonstrate mastery of user input/output in this lab by setting up your menus and
responses such that the user gets sensible feedback for non-sensible input. Your code should not
crash, and should prompt the user for better input if they give bad input. For example, if they
choose menu options that don’t exist, or enter invalid dates or words instead of numbers for
amount of plastic on a given day.
1This is a real project... just not the real name for it, check out https://theoceancleanup.com/oceans/ for
more info
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Hints
Here are a few hints that might help you with this assignment:
• Break the problem down: don’t worry about calculating totals while you’re worried about
getting user input. Do all the user input parts first and just leave a comment saying
#calculate total here or #calculate overload days here, and come back to those
separately
• Use comments: this is a big lab, it can be easy to get lost. Plan out your code with comments
first, and make sure you use your comments to remind yourself what you’re doing where
• Think about your if statements: you can do this just using lots of ifs, but your life will be
easier if you set up appropriate if/elif/else structures
Extra Practice
If you finish early and want to practice more, here are a few things you can try:
• Completing the mastery portion isn’t a lot of work, but it is time consuming. Making idiot
proof code is difficult, because there are a lot of very resourceful idiots out there.
• Try to add additional options such as retrieving the maximum or minimum amount of plastic
removed in a given date range
• Try to improve the user input experience, so that the user can enter several days at once
(e.g., “enter plastic for next day or ‘E’ to exit”)