Day 12: Error Correction Techniques

Learning Objectives

• CRD-2.I: Describe how a code segment or program functions.
• CRD-2.J: Identify and correct errors in algorithms and programs, including error discovery through testing.

Essential Questions

• What techniques can programmers use to find and fix errors?
• How can systematic debugging improve program development?

Materials Needed

• Presentation slides on debugging techniques
• Sample programs with errors for debugging
• Debugging tools/environment
• Debugging activity worksheet

Vocabulary

• Debugging
• Test case
• Hand tracing
• Visualization
• Debugger
• Breakpoint
• Watch variable
• Edge case

Procedure (50 minutes)

Opening (8 minutes)

1. Review and Connection (3 minutes)

   • Review error types from previous lesson
   • Connect to today's focus on finding and fixing errors

2. Warm-up Discussion (5 minutes)

   • Prompt: "What strategies do you currently use when your code doesn't work?"
   • Create a class list of debugging approaches

Main Activities (32 minutes)

3. Lecture: Techniques for Finding and Correcting Errors (12 minutes)

   • Explain test cases:
     • Creating inputs with expected outputs
     • Testing boundary conditions
     • Testing typical and atypical scenarios
   • Explain hand tracing:
     • Manually executing code step by step
     • Tracking variable values on paper
     • Finding logical errors through manual execution
   • Explain visualizations:
     • Using diagrams to understand program flow
     • Visualizing data structures and algorithms
   • Explain debuggers:
     • Setting breakpoints
     • Watching variables
     • Stepping through code
     • Examining the call stack

4. Demo: Using Different Debugging Techniques (10 minutes)

   • Demonstrate each technique with a sample error:
     • Show how to create and use test cases
     • Walk through hand tracing a simple algorithm
     • Use visualization tools to understand program flow
     • Demonstrate debugger features
   • Show how different techniques are suited for different error types

5. Lab: Practice Using Debugging Techniques (10 minutes)

   • Provide students with programs containing various errors
   • For each program, students apply appropriate debugging techniques:
     • Create test cases to expose the error
     • Hand trace the algorithm
     • Use the debugger to find the issue
     • Fix the error and verify the solution

Closing (10 minutes)

6. Debugging Challenge (7 minutes)

   • Provide students with a program containing multiple types of errors
   • Students must find and fix all errors
   • Students document which debugging techniques they used for each error

7. Preview Next Lesson (3 minutes)

   • Explain that next class will begin the collaborative program development project
   • Ask students to think about potential program ideas for the project

Assessment

• Formative: Quality of debugging technique application in lab
• Debugging Challenge: Ability to find and fix multiple error types

Differentiation

For Advanced Students

• Provide programs with more subtle and interrelated errors
• Challenge them to create their own debugging tools or visualizations
• Ask them to compare efficiency of different debugging approaches

For Struggling Students

• Offer more structured guidance on which techniques to apply
• Provide hints about error locations
• Allow pair programming during debugging activities

Homework/Extension

• Debug a program with multiple errors using at least three different techniques
• Create a debugging guide for a specific type of program
• Research and report on advanced debugging tools or techniques

Teacher Notes

• Emphasize that systematic debugging is more effective than random changes
• Connect debugging to the iterative development process
• Point out that the AP exam may ask about debugging techniques
• Remind students that these skills will be essential for their collaborative project