Aftab Ahmed's Blog

My 100-Day Python Journey: Debugging Adventures on Day 12

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Aftab Ahmed
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3 min read

Introduction

Hey there, fellow tech enthusiasts and aspiring programmers! Welcome back to my 100-day Python programming journey. Today, I'm thrilled to share my Day 12 experiences with you, as I delved deep into the world of debugging. It's been quite the rollercoaster ride, but I promise you, it's been worth every twist and turn!

1. Describe the Problem

Debugging, in essence, is like solving a mystery. You start with a problem, an error, or unexpected behavior in your code, and your mission is to unravel it. On Day 12, I was working on a program to calculate Fibonacci numbers, and surprise, surprise, I ran into a bug.

2. Reproduce the Bug

The first step in debugging is to recreate the issue consistently. I realized my Fibonacci function wasn't returning the expected results. To recreate the problem, I ran the code several times with different input values, and each time, the results were far from what I had anticipated.

def fibonacci(n):
    if n <= 1:
        return n
    else:
        return fibonacci(n-1) + fibonacci(n-2)

result = fibonacci(5)
print(result)  # Expected output: 5, but I got 8!

3. Play Computer and Evaluate Each Line

Debugging often involves playing the role of a computer. I meticulously went through my code, line by line, keeping a close eye on variables and calculations. I realized that my Fibonacci function had a bug in the recursive logic. It wasn't considering the base cases correctly.

def fibonacci(n):
    if n <= 0:  # Fixed the base case here
        return 0
    elif n == 1:  # Fixed the base case here
        return 1
    else:
        return fibonacci(n-1) + fibonacci(n-2)

4. Fixing Errors and Watching for Red Underlines

As I made these changes, I was keeping a close watch on the code editor for any red underlines or syntax errors. Fixing those was straightforward, but it's essential to be vigilant and ensure your code is error-free.

5. Squash Bugs with a print() Statement

Sometimes, the best tool in your debugging arsenal is the humble print() statement. I added some print statements to trace the execution of my Fibonacci function, which was incredibly helpful in visualizing what was going wrong.

def fibonacci(n):
    if n <= 0:
        return 0
    elif n == 1:
        return 1
    else:
        print(f"Calculating Fibonacci({n})")
        return fibonacci(n-1) + fibonacci(n-2)

6. Bringing Out the Big Gun: Using a Debugger

For more complex issues, a debugger is your best friend. I used Python's built-in debugger (pdb) to set breakpoints, inspect variables, and step through the code. It provided a clearer picture of what was happening and where the problem was.

import pdb

def fibonacci(n):
    if n <= 0:
        return 0
    elif n == 1:
        return 1
    else:
        pdb.set_trace()  # Set a breakpoint
        return fibonacci(n-1) + fibonacci(n-2)

7. Final Debugging Tips

Before I wrap up this exciting debugging journey, here are some key takeaways:

  • Stay patient: Debugging can be frustrating, but remember, every bug you squash makes you a better programmer.

  • Test incrementally: Don't write a massive chunk of code without testing it incrementally. Small, focused tests can help pinpoint issues early.

  • Use descriptive variable names: Clear and descriptive variable names can make it easier to spot errors.

  • Don't hesitate to ask for help: Sometimes, a fresh pair of eyes can spot what you've missed.

Conclusion

And there you have it, my Day 12 adventures in debugging. It was a day filled with challenges, but I emerged stronger and more confident in my programming skills. Remember, debugging is a skill that improves with practice, so keep coding, keep debugging, and keep learning!

Happy coding, everyone! Stay tuned for more updates from my 100-day Python journey.

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