Introduction to Debugging Basics

Debugging can be likened to playing "Where's Waldo," where small details in large programs can lead to errors.

Key Debugging Strategies

1. Attention to Detail
   • Even minor syntax errors can cause problems (e.g., typos).
   • Look for small errors: typos in variable names, syntax errors in functions, if statements, or loops.
   • Code might be valid but not what was intended.
2. Questioning Assumptions
   • Computers execute exactly what they're told, errors arise from incorrect instructions.
   • Overlooking simple details, misunderstanding problem descriptions, or mixing up pre and post conditions are common issues.
   • Be open to the problem being in unexpected parts of the code.

Strategies for Effective Debugging

• Double-check code regularly to catch tricky bugs which often have simple sources.
• Useful in both small problems (e.g., ten-line code) and large codebases (e.g., million-line code).

Debugging Example: Running Laps with Karel

Scenario 1: Syntax Error

• Problem: Error on line 16 due to missing parentheses in the for-loop.
• Solution: Add parentheses around range, allowing the loop to execute correctly.

Scenario 2: Logic Error

• Problem: Karel runs too many laps due to running 5 sides instead of 4.
• Solution: Correct the range to ensure only 4 laps are executed.

Conclusion

• Debugging begins with careful attention to detail and continuously questioning assumptions.
• Practice these strategies to improve debugging skills and ensure code correctness.