Doxygen is a very cool documentation generator (HTML, LaTeX, RTF, PDF, etc) for C, C++ and IDL. 

Free, portable, actively developed with a set of good mailing lists for support and developers.

http://www.doxygen.org/

See also: GraphViz, DocPlusPlus, JavaDoc, CppDoc

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"Doxygen is a documentation system for C++, C, Java, IDL (Corba and Microsoft flavors) and to some extent PHP and C#. Doxygen can generate an on-line documentation browser (in HTML) and/or an off-line reference manual ... The documentation is extracted directly from the sources, which makes it much easier to keep the documentation consistent with the source code."

http://www.stack.nl/~dimitri/doxygen/

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Doxygen is a BarelyLiterateProgramming system.

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For ObjectiveCee, we have AutoDoc and HeaderDoc. The latter ships with ExCode on Panther (MacOsx 10.3). AutoDoc has been around since NextStep/OpenStep.

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CategoryDocumentation CategoryCpp