Since C++ is a "Multi-Paradigm" language your study of C++ code should include the various different expressions of the language. Also it is best if you can hav

Since C++ is a "Multi-Paradigm" language your study of C++ code should include the various different expressions of the language. Also it is best if you can have a book explaining and walking you through the codebase. To that end i can suggest the following from my own experience; * To study OO expression of C++ via Class libraries/Frameworks i recommend a study of "Microsoft Foundation Classes (MFC) library" paired with the book MFC Internals. The code is available with the installation of Visual Studio. * P.J.Plauger's The Standard C Library and The C++ Standard Template Library(with Alexander Stepanov, Meng Lee and David Musser) will teach you excellent C and C++ Generic programming skills. Code available with the standard C++ toolchain installation. * The Boost libraries paired with the book C++ Template Metaprogramming: Concepts, Tools, and Techniques from Boost and Beyond. * The FXT library of Algorithms by Jorg Arndt (https://www.jjj.de/fxt/fxtpage.html https://www.jjj.de/fxt/fxtpage.html) along with its book Matters Computational for writing optimized C++ code. I would also suggest reading the following two classics to learn designing in C++; * Multi-Paradigm Design for C++ by James Coplien. * Scientific and Engineering C++: An Introduction with Advanced Techniques and Examples by Barton and Nackman.