Explaining functional programming to object-oriented programmers and less technical people

Question

What are some good examples that I can use to explain functional programming?

The audience would be people with little programming experience, or people who only have ob

Answer 1

It might be easier to describe functional programming by its fundamental characteristics first:

1. Functions (obviously)
2. There are no side effects
3. Immutability
4. Recursion is very important
5. Very Parallelizable

Of these, the most important characteristic is the notion of no side effects, as the other characteristics follow from that.

Functional programming is used in places you might not expect. It is used to run traffic lights and communications switches (Ericsson switches run Erlang), for example.