We will discuss and describe two different styles of programming, imperative programming and declarative programming. Functional programming is a subset of declarative programming. The easiest way to explain what declarative programming is to compare it to its opposite, imperative programming. Imperative programming focuses on how the program should achieve its result. Functional programming, on the other hand, is a declarative programming paradigm, which means its focus is on what the programming should accomplish, or the what. This is an important distinction.