C/C++ header and implementation files: How do they work?

Question

This is probably a stupid question, but I\'ve searched for quite a while now here and on the web and couldn\'t come up with a clear answer (did my due diligence goo

Answer 1

int myfunction(int); is the function prototype. You declare function with it so that compiler knows that you are calling this function when you write myfunction(0);.

And how do the header and main function even know the function definition exists?
Well, this is the job of Linker.