What is the need to declare and define functions separately?

Question

Besides making the code look more organized, is there any real benefit in declaring the function early and defining it later?

Answer 1

you can declare and define function simultaneously

but if you declare first then define it later

it make code more organised and readable for professional as well more easy to understand for a newbie

Answer 2

Right. So I can just define every function before main() then?
Thanks.