What Is The Functional Programming ?

Answer 1

mainly it means using functions to program. another charchteristic of fp is stateless, meaning variables don't change states by being immutable.
examples of fp languages are Haskell, and to a lesser extent also JavaScript.

Answer 2

it is a way to solve problems. in it functions can be returned from other functions, functions can take functions as argument.
as a result, most functions are highly generic and can take a wide range of types as argument.
Python fulfills these. Though not considered a full functional programming language, this will give you a start.

Answer 3

Think of it as coding with equations or value returning methods only. Once a variable has been declared it can not be changed later on, so we can say there is only one scope. Every line is a declaration instead of being a statement. That's the simplest way to put it. If you look up "Lambda-Calculus" you'll gain an intuitive understanding of what Functional Programming is.