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C++ has several powerful features available for debugging no matter which platform you use, whether or not you have access to a debugger. The purpose of this article is to enumerate the methods you can use to debug your code, and discuss circumstances for their use.

When finding out about a new feature in a programming language, one's first inclination is often to ignore its drawbacks and try to substitute it for all other features. Since no design model is perfect for every problem, this inclination is wasteful and merely leads to poorly designed code, since everything must be made to fit into the "better" design model.

You cannot choose the most suitable model without first considering your circumstances and the relative strengths and weaknesses of several different methods. Assertions, exceptions, logging, return values, etc. all have specific strengths and weaknesses.

I'll list some of my observations on these methods.

Method 0 - Nothing

Pros: Easy to write tons of code, imposes no execution burden in debug or release builds

Cons: Better skip the country if it doesn't work

This method is more of a non-method - that's why it is called method 0. I thought I'd include it for completeness. If you use this method often, do your clients a favor and seek professional help.

It also gives me a chance to explain the theory of debugging as I see it and some conventions we'll use throughout this article. There are basically two versions of code in C++ - debug and release. The code must be functionally equivalent in both modes. The difference is that in debug mode we favor useful debugging aids over speed, and in release mode we often value speed over debugging. Of course, you can define different levels if need be, but for this article we'll only use two.

Note that debugging is different than cleanup.

Bugs are typically poorly designed code that fails under certain conditions. Debugging is the process of finding and eliminating bugs. There are many causes of bugs, but here is a short list:

  1. Poor understanding of the language, API, other code, and/or platform
  2. Bad code design/organization
  3. Operating System bugs
  4. Miscommunication between members of a team
  5. Hastily written code
  6. Absolutely no reason at all :)

Note that when you write code, your code is rarely completely independent. Viz., your code is typically dependent on the standard library. Further, you will rarely code alone (if you intend to be a commercial success), which means interdependencies will exist between your code and that of your team members, and possibly that of your customers (if you code libraries).

Two terms are often used to describe the roles of people or source code as they relate to depencies: server and client. People who use and depend on your code are said to be clients. When you depend on their code, you are their client. Server is rarely used here, but it means "the person who wrote the code."

Next : Assertions