“Seibel: What are the techniques that you use there? Print statements?

Armstrong: Print statements. The great gods of programming said, "Thou shall put printf statements in your program at the point where yout hink it's gone wrong, recompile, and run it.

Then there's -- I don't know if I read it somewhere or if I invented it myself -- Joe's Law of Debugging, which is that all errors will be plus/minus three statements of the place you last changed the program.”