Why we need to declare a function

Question

C language
What is the point in declare a function before the description when it can run without it.

Answer 1

Imagine you have two functions that call each other.

But if the called function is not at least declared yet, you'll get an error when the name comes up in a function body.

By declaring everything at the top, these things don't matter any longer.

(This is one of the points.)

Answer 2

if I get you right, you're trying to say, why not just write everything at the top there, why bother declare and then give description, that depends on your choice, either way works fine to me