Haskell is a standardized, general-purpose compiled purely functional programming language, with non-strict semantics and strong static typing.
Haskell is a functional language, where we focus on functions which take immutable values as input and produce new values as output. Furthermore, Haskell is a lazy language and it defers computation until the result is actually needed.
Haskell has profoundly different paradigm of programming and hence a typical haskell program looks quite different than a traditional program in C, Python, or Java.
Sample program of quicksort in Haskell: