Defect Prevention

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Defect prevention means to avoid defects before and during coding, instead of finding and removing them afterwards.

14 Suggestions

Some suggestions what could be done to prevent defects during software development:


Agree on and commit to a mandatory set of coding and design standards. Issues to be covered: Design, C++ usage, documentation, complexity, maintainability, interface design, error-handling, coding in general, use of standard solutions for standard problems.

Code Reviews

Establish regular code peer reviews. Use code you work upon. Use coding standards as reference and/or discuss what is really important to you. Change partners often and across domain-borders.

Personal Favourite Defect List

Keep a private list of your "favourite" bug causes and standard violations. Use that for continuous improvement.

Expand Developer Tests

When coding, test your code as if their would not be any QA later and all users' satisfaction would depend on you alone.

Use Unit Tests

Write unit tests and run them regularly. All unit tests have to pass.

Smallest Possible Steps

Adopt a habit of developing a feature in the smallest possible steps: The cycle of develop -> test -> develop -> test ... should be as short as possible, usually much shorter than a day.

Warning Free Code

The compiler is your first and free check against dubious code. Program such that there are no compiler warnings.

Dynamic Code Checks

Use Valgrind memcheck or similar tools to dynamically check your code against memory corruption.

Static Code Checks

Find and use tools that can statically check your code for correctness and maintainability. Currently most useful tools for this are not yet free/open-source but this may change.


Educate yourself regularly. E.g. the knowledge about writing good C++ has changed enormously within the last 10 years.

Make Quality a Goal

Make the quality of your code just as important as the functionality. Indeed the quality is part of the functionality.

Plan for Quality

High quality coding needs more time than hacking. Plan for that. You get the time back by less bugs and easier code maintenance.

Analyse Bugs

Find out how bugs came into life, explore the reasons (inside and outside the code itself), change what caused the defects.


If code is difficult to understand or a continuous source of bugs, refactor it, until it is easy to maintain.

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