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Some comments on comments

Recently we have been discussing coding guidelines at work. A topic that often pops up during such discussions are Comments. What should be commented, how should the comments be formulated etc.

Personally I have the following preferences when it comes to comments in code:

  • A comment should explain why a piece of code does what it does, not what the code does.
  • If you feel a piece of code needs a comment. See if it is possible to make the code easier to understand rather than commenting it.
  • Only use special mark-up like Doxygen if you actually generate documentation from it. I have seen cases where Doxygen-like syntax was used all over the code, only obfuscating the text.
  • Public interfaces intended for users of your lib/class should be documented, and documented well.
  • Internal/private interfaces and classes does not require documentation. Put effort on making the code really easy to understand rather than adding a bunch of comments.
  • Keep comments short and clear.
Happy commenting!

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