Debugging mindset in Intro to Computing - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the primary goal of a debugging mindset?

The primary goal is to find and fix errors in a program by carefully understanding the problem and testing solutions step-by-step.

beginner

Why is patience important in debugging?

Patience helps you stay calm and focused while investigating problems, which often take time and multiple attempts to solve.

beginner

How can breaking a problem into smaller parts help in debugging?

Breaking a problem into smaller parts makes it easier to isolate where the error happens, like checking each piece of a puzzle separately.

intermediate

What role does asking questions play in debugging?

Asking questions helps you understand what the program should do, what it actually does, and where things might be going wrong.

intermediate

Explain the importance of testing changes after fixing a bug.

Testing ensures that the fix works and does not cause new problems, similar to checking a repaired machine to make sure it runs smoothly.

What is the first step in a good debugging process?

A Understand the problem clearly

B Change the code randomly

C Ignore error messages

D Restart the computer

Understanding the problem clearly helps you know what to look for before making any changes.

Why should you test your program after fixing a bug?

A To make sure the bug is fixed and no new bugs appeared

B To make the program slower

C To confuse other developers

D To delete the code

Testing confirms the fix works and prevents new errors from being introduced.

Which attitude helps most when debugging?

A Guessing randomly

B Frustration and rushing

C Ignoring details

D Patience and curiosity

Patience and curiosity keep you calm and motivated to find the root cause.

How does breaking a problem into smaller parts help debugging?

A It hides the error

B It isolates where the error is

C It makes the problem bigger

D It deletes the problem

Smaller parts are easier to check and understand, helping locate the error.

What should you do if you don’t understand an error message?

A Restart without saving

B Ignore it and continue

C Ask questions or look up the message

D Delete the program

Asking or researching helps you understand and fix the problem effectively.

Describe the key steps you take when you start debugging a program.

Think about how you approach a puzzle or a broken machine.

Explain why having a calm and patient mindset is important during debugging.

Consider how patience helps in solving difficult problems in daily life.

Practice

1. What is the main goal of having a debugging mindset when working with code?

easy

A. To ignore error messages and keep coding

B. To write code as fast as possible without testing

C. To carefully check and fix code step-by-step

D. To copy code from others without understanding

Solution

1. Step 1: Understand the purpose of debugging mindset

   Debugging mindset means being careful and systematic in finding and fixing errors in code.

2. Step 2: Compare options with this purpose

   Only To carefully check and fix code step-by-step matches this careful step-by-step checking and fixing approach.

3. Final Answer:

   To carefully check and fix code step-by-step -> Option C

4. Quick Check:

   Debugging mindset = careful step-by-step fixing [OK]

Hint: Debugging means careful step-by-step checking [OK]

Common Mistakes:

• Thinking debugging is about coding fast
• Ignoring error messages
• Copying code without understanding

2. Which of the following is the correct way to write a comment in Python to help with debugging?

easy

A.

B. # This is a comment

C. /* This is a comment */

D. // This is a comment

Solution

1. Step 1: Identify Python comment syntax

   Python uses the # symbol to start a comment line.

2. Step 2: Match options with Python syntax

   # This is a comment uses #, which is correct. Others are comment styles for HTML, JavaScript, or C.

3. Final Answer:

   # This is a comment -> Option B

4. Quick Check:

   Python comment = # [OK]

Hint: Python comments start with # symbol [OK]

Common Mistakes:

• Using // or /* */ which are not Python comments
• Using HTML comment syntax in Python

3. Consider this Python code snippet:

def add_numbers(a, b):
    return a + b

result = add_numbers(3, '4')
print(result)

What will happen when this code runs?

medium

A. It raises a TypeError

B. It prints 34

C. It prints 7

D. It prints null

Solution

1. Step 1: Analyze the function call with mixed types

   The function tries to add an integer 3 and a string '4'.

2. Step 2: Understand Python's behavior on adding int and str

   Python cannot add int and str directly, so it raises a TypeError.

3. Final Answer:

   It raises a TypeError -> Option A

4. Quick Check:

   int + str = TypeError [OK]

Hint: Adding int and str causes TypeError in Python [OK]

Common Mistakes:

• Thinking Python concatenates int and str
• Expecting numeric addition without type conversion

4. You have this JavaScript code:

let count = 0;
for(let i = 0; i < 5; i++) {
  count = count + i;
}
console.log(count);

But the output is always 0. What is the most likely error?

medium

A. The console.log statement is missing

B. The loop condition is wrong, it never runs

C. The variable count is declared with let outside the loop

D. The variable count is reset inside the loop

Solution

1. Step 1: Check where count is updated

   If count is reset to 0 inside the loop each time, it never accumulates.

2. Step 2: Identify the cause of output always 0

   Resetting count inside the loop causes it to stay 0 after loop ends.

3. Final Answer:

   The variable count is reset inside the loop -> Option D

4. Quick Check:

   Resetting accumulator inside loop = no sum [OK]

Hint: Check if accumulator resets inside loop [OK]

Common Mistakes:

• Assuming loop never runs
• Ignoring variable reset inside loop
• Thinking console.log missing causes no output

5. You want to debug a program that processes a list of numbers but sometimes skips numbers unexpectedly. Which approach best uses a debugging mindset to find the problem?

hard

A. Add print statements inside the loop to trace each number processed

B. Delete the entire code and rewrite it from scratch

C. Ignore the problem and hope it fixes itself

D. Change random parts of the code without testing

Solution

1. Step 1: Choose a systematic way to observe program behavior

   Adding print statements inside the loop helps see which numbers are processed.

2. Step 2: Use this information to identify where skipping happens

   Tracing output step-by-step reveals logic errors causing skips.

3. Final Answer:

   Add print statements inside the loop to trace each number processed -> Option A

4. Quick Check:

   Trace program flow step-by-step to debug [OK]

Hint: Trace code step-by-step with print statements [OK]

Common Mistakes:

• Rewriting code without understanding
• Ignoring errors
• Changing code randomly without testing