The calculator project is the most complicated one, being the last. I recommend following the six steps I outline in Exploration 74. The files below show the evolution of my solution as I follow the six steps. The parser undergoes the greatest change, although its central spirit remains the same throughout all steps.
In this project, I use Google Test for the unit-testing framework. The project was just too complicated for the trivial test.hpp file that other projects use.
See also the main chapters page.