Functional programming (FP) is a programming paradigm that emphasizes the use of functions to solve problems. FP avoids mutable state and side effects, which can make code more predictable and easier to reason about. Popular functional programming languages include Haskell, Lisp, and Scala. Check our reviews An operating system (OS) is a software system that manages computer hardware and software resources and provides common services for computer programs. Examples of operating systems include Windows, macOS, and Linux.