Although the functional paradigm is old (it was born in the 1950s), it didn't take the world of programming by storm. Most of the dominant paradigms these days include imperative and object-oriented languages. As we've stated many times in this and many other books, C++ is a multi-paradigm language. That's the beauty of studying C++; we can tune it to fit almost every environment. Grasping the paradigm is not an easy task. You have to feel it and apply it until you finally start thinking in terms of the paradigm. After that, you will see solutions to regular tasks in a matter of seconds.
If you can remember when you first time learned about object-oriented programming, you might recall the principles that made you struggle a bit before you could unlock the true potential of OOP. The same is true for functional programming. In...