Ignoring all extraneous files, this is the structure that this project uses:

project-name/
├── CMakeLists.txt
├── cmake/
│   └── Modules/
│       └── CodeCoverage.cmake
├── doc/
│   ├── CMakeLists.txt
│   ├── Doxyfile.in
│   ├── directory_structure.md
│   ├── main_page.md
│   └── ...
├── include/
│   └── project-abbr/
│       ├── config.hpp.in
│       ├── factorial.hpp
│       └── hello_world.hpp
├── src/
│   ├── factorial.cpp
│   ├── hello_world.cpp
│   └── main.cpp
├── test/
│   ├── CMakeLists.txt
│   ├── factorial_test.cpp
│   ├── hello_world_test.cpp
│   └── test_runner.cpp
└── third_party/
    └── doctest/
        └── doctest.h

This may all look very complex, but here is an explanation of all of the directories:

Directory	Purpose
`cmake`	Contains all CMake related configuration files.
`doc`	Contains Doxygen configuration files, which can be used to create documentation for the project using the CMake target `doc`.
`include`	Contains all the project public include files, namespaced in a directory which is an abbreviation of the project name.
`src`	Contains the implementations of all files in `include`. Private level includes and implementations are also in this directory.
`test`	Contains test files to unit test the library portion of the application.
`third_party`	Contains CMake configuration files for third party dependencies or single header files for projects with single includes.