Diagnostics and Debugging

Software is complex; however, well you design your code, at some point you'll have to debug it, whether during the normal testing phases of developing your code, or when a bug report has been issued. It's prudent to design your code to make testing and debugging as straight forward as possible. This means adding tracing and reporting code, determining invariants and pre- and post-conditions, so that you have a starting point to test your code, and writing functions with understandable and meaningful error codes.