FC++ is a library for functional programming in C++. Functional programming is a programming paradigm in which functions are treated as regular values. Thus, we can have functions that take other functions as parameters. The former functions are called ”higher-order” functions. A common feature of functions is that they can be polymorphic. ”Polymorphic” means that the same function can be used with arguments of many types. FC++ is distinguished from other libraries (including the C++ Standard Library) by its complete support for polymorphism: FC++ polymorphic higher-order functions can take other polymorphic functions as arguments and return polymorphic functions as results. This is particularly useful (i.e., simplifies code) in C++ where type inference is limited and we often need to pass polymorphic functions around and determine their type later. With FC++ you can define your own higher-order polymorphic functions, but the library also contains a large amount of functionality that can be re-used as-is in C++ programs. This includes infinite (”lazy”) lists, useful higher-order functions (like map, compose, etc.), a reference-counting facility that can be used to replace C++ pointers, many common logical and arithmetic operators in a form that can be used with higher-order functions, and more