Lesson 12 of 20 · Debugging

Debugging — Part 12

Find and fix mistakes so the program does what you want.

What you'll learn

You will learn to read code carefully to find mistakes (bugs) and understand how to fix them.

Words to know

Bug: A mistake in the code that makes the program do something wrong or unexpected.
Debug: To find and fix bugs. You look at the code and the output to figure out what's wrong.
Fix: To change the code so it works correctly. Fixing bugs is part of coding.

Your turn

📋 Show the steps

Try it: run the code, then change it

1Read the code line by line: x is 2, y is 3, z is x + y which is 5. The output would be 'Total: 5'. This code is correct!
2Now imagine the last line was print('Total:', x) by mistake. It would show 'Total: 2' — wrong! That's a bug.
3Debugging means reading code carefully, finding where it goes wrong, and fixing it. It's like being a detective!
4Every coder — even experts — writes bugs. The skill isn't avoiding bugs, it's being good at finding and fixing them!

Auto-run is on: change the code and the result updates by itself.

Auto-run

Output

Loading Python... This may take a few seconds.

Check your understanding · 1 of 5

print("Hello) What's the bug?

Check your understanding · 2 of 5

How do you find a bug?

Check your understanding · 3 of 5

x = 5 y = 0 print(x + z) What's the bug?

Check your understanding · 4 of 5

What is a bug in code?

Check your understanding · 5 of 5

What is debugging?

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