This book isn’t meant to teach the C++ programming language. It’s about functional programming and how it fits in with C++. Functional programming provides a differ- ent way to think about software design and a different way of programming, compared to the imperative, object-oriented styles commonly used with C++. Many people who see the title of this book may find it strange, because C++ is com - monly mistaken for an object-oriented language. Although C++ does support the object-oriented paradigm well, it goes much further than that. It also supports the pro- cedural paradigm, and its support for generic programming puts most other languages to shame. C++ also supports most (if not all) functional idioms quite well, as you’ll see. Each new version of the language has added more tools that make functional program- ming in C++ easier.