Week 1: Conditionals

This week you'll complete 5 problems that all use conditional statements (if, if/else, if/elif/else blocks).

Learning Resources

Don't know about conditionals yet? CS50 has you covered with multiple ways to learn:

Full Lecture (1 hour)

Watch the complete Week 1 lecture:
https://www.youtube.com/watch?v=_b6NgY_pMdw

Read the Notes

Skim the prepared notes if you prefer reading:
https://cs50.harvard.edu/python/notes/1/

Short Videos (5-10 minutes each)

Watch specific topics:

• Conditionals: https://cs50.harvard.edu/python/shorts/conditionals/
• Boolean Expressions: https://cs50.harvard.edu/python/shorts/boolean_expressions/

Jump Right In

Or just figure stuff out as you go! The problem descriptions will guide you.

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Assignment Overview

Complete ALL of the following problems from CS50P Week 1:

1. Deep Thought - The answer to life, the universe, and everything
2. Home Federal Savings Bank - Greetings and money
3. File Extensions - Determine media types
4. Math Interpreter - A calculator program
5. Meal Time - Is it time to eat?

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Problem 1: Deep Thought

📁 deep/deep.py
🔗 https://cs50.harvard.edu/python/psets/1/deep/

Implement a program that prompts the user for the answer to the Great Question of Life, the Universe and Everything. Output Yes if the user inputs 42 or (case-insensitively) forty-two or forty two. Otherwise output No.

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Problem 2: Home Federal Savings Bank

📁 bank/bank.py
🔗 https://cs50.harvard.edu/python/psets/1/bank/

Implement a program that prompts the user for a greeting:

• If the greeting starts with "hello", output $0
• If the greeting starts with "h" (but not "hello"), output $20
• Otherwise, output $100

Ignore any leading whitespace in the user's greeting, and treat it case-insensitively.

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Problem 3: File Extensions

📁 extensions/extensions.py
🔗 https://cs50.harvard.edu/python/psets/1/extensions/

Implement a program that prompts the user for a file name and outputs that file's media type if the file's name ends (case-insensitively) in any of these suffixes:

• .gif
• .jpg
• .jpeg
• .png
• .pdf
• .txt
• .zip

If the file's name ends with some other suffix or has no suffix at all, output application/octet-stream.

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Problem 4: Math Interpreter

📁 interpreter/interpreter.py
🔗 https://cs50.harvard.edu/python/psets/1/interpreter/

Implement a program that prompts the user for an arithmetic expression and then calculates and outputs the result as a floating-point value formatted to one decimal place.

Assumptions:

• User's input will be formatted as x y z (with spaces)
• x is an integer
• y is +, -, *, or /
• z is an integer
• If y is /, then z will not be 0

Example: If the user inputs 1 + 1, your program should output 2.0.

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Problem 5: Meal Time

📁 meal/meal.py
🔗 https://cs50.harvard.edu/python/psets/1/meal/

Implement a program that prompts the user for a time and outputs whether it's breakfast time, lunch time, or dinner time. If it's not time for a meal, don't output anything at all.

Assumptions:

• User's input will be formatted in 24-hour time as #:## or ##:##
• Each meal's time range is inclusive

Required structure:

def main():
    ...

def convert(time):
    ...

if __name__ == "__main__":
    main()

The convert function should convert time (a string in 24-hour format) to the corresponding number of hours as a float. For instance, "7:30" should return 7.5.

Challenge (Optional):
Add support for 12-hour times:

• #:## a.m. and ##:## a.m.
• #:## p.m. and ##:## p.m.

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Testing Your Code

Before submitting, test each problem with check50:

check50 cs50/problems/2024/python/deep
check50 cs50/problems/2024/python/bank
check50 cs50/problems/2024/python/extensions
check50 cs50/problems/2024/python/interpreter
check50 cs50/problems/2024/python/meal

(Note: Remove --local flag - it's not needed)

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Saving Your Work

After completing each problem:

1. Click the Source Control icon (left sidebar)
2. Stage your changes (click the + button)
3. Type a commit message (e.g., "Complete deep thought")
4. Click Commit
5. Click Sync Changes

Do this after each problem so your work is saved!

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Submission

When you've completed all five problems:

• Make sure all files are committed and synced
• Your work will be automatically recorded

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Getting Help

• Review the problem specifications at the CS50 links above
• Watch the lecture or shorts if you're stuck on concepts
• Test your code with different inputs
• Ask for help if needed!