Doxygen

https://www.doxygen.nl/index.html

wikipedia

Doxygen is the de facto standard tool for generating documentation from annotated C++ sources, but it also supports other popular programming languages such as C, objective-C, C#, PHP, Java, Python, IDL, Fortran, VHDL and to some extent D.

Doxygen can help you in three ways:

1. It can generate an on-line documentation browser (in HTML) and/or an off-line reference manual (in LATEX) from a set of documented source files. The documentation is extracted directly from the sources, which makes it much easier to keep the documentation consistent with the source code.
2. You can configure doxygen to extract the code structure from undocumented source files.
3. You can slso use doxygen for creating normal documentation

Documentation