15.1 Review the methods

15.1.1 Review now

Now is a good time to evaluate whether you have learned anything from reading this book and what you want to put into practice. The tables in this section list all the techniques described in this book. If you don’t know how to use a technique, go back and reread the corresponding section.

The columns give you space to decide how to apply the technique. If you’re already using the technique, check the first column. If you would like to use the technique at the next opportunity, check the second column. If you would like to use the technique at some future time, check the third column. Put more checks in the third column than the second one. You can’t use everything first. If you don’t think the technique is applicable to your work, check the last column.

Table 15.1: Debugging Techniques, Part 1
Technique	Already Using	Use Soon	Use Later	No Plans
Use cross-disciplinary knowledge
Focus on facts
Pay attention to unusual details
Gather facts before hypothesizing
State the facts to someone else
Start by observing
Don’t guess
Exclude alternative explanations
Reason in both directions
Watch for red herrings
Use alibis as clues
Eliminate impossible causes
Exercise curiosity
Reason based on facts
Enumerate possibilities
Use the power of logic
Use a system for organizing facts
Exercise caution when searching
Use gestalt understanding
Show how something could be done
Don’t look for it
It isn’t lost—you are

Debugging Techniques, Part 2
Technique	Already Using	Use Soon	Use Later	No Plans
Remember the three c’s
It’s where it’s supposed to be
Look for domestic drift
You’re looking right at it
The camouflage effect
Think back
Look once, look well
The eureka zone
Tail thyself
It wasn’t you
Use a binary search strategy
Use a greedy search strategy
Use a breadth-first search strategy
Use a depth-first search strategy
Use a program slice strategy
Use a deductive-analysis strategy
Use a inductive-analysis strategy
Stabilize the program
Create a test case
Reduce the required input
Categorize the problem
Describe the problem
Explain the problem to someone else

Debugging Techniques, Part 3
Technique	Already Using	Use Soon	Use Later	No Plans
Recall a similar problem
Draw a diagram
Choose a hypothesis from historical data
Read the code
Write unit tests
Display variable values
Display execution messages
Display procedure arguments
Generate a flow trace
Generate a variable snapshot
Generate a memory dump
Force a variable value
Assert assumptions
Check data structures
Display data structures
Use runtime subscript checking
Use runtime stack checking
Use runtime heap checking
Initialize global variables
Initialize local variables
Change storage class
Use a different compiler
Compile to an intermediate level
Execute on a different platform

15.1.2 Review later

Keep the list near you when you’re doing debugging work. When you’re working on a difficult bug, look over the list and see if any of the techniques might help you. If you use one of the techniques for the first time, write the date in the table.