Why can't a function go after Main

Question

Why can't I put a function after main, visual studio cannot build the program. Is this a C++ quirk or a Visual Studio quirk?

eg.

int main()
{
   myFunction()
}

myFunction(){}

will produce an error that main cannot use myFunction

Answer 1

most of the computer programming languages have top to down approach which means code is compiled from the top. When we define a function after main function and use it in the main [myFunction () ], compiler thinks " what is this. I never saw this before " and it generates an error saying myFunction not declared. If you want to use in this way you should give a prototype for that function before you define main function. But some compilers accept without a prototype.

#include<stdio.h>
void myFunction(); //prototype
int main()
{
   myFunction(); //use 
}

myFunction(){ //definition 
.......;
}

Answer 2

You can, but you have to declare it beforehand:

void myFunction(); // declaration

int main()
{
   myFunction();
}

void myFunction(){} // definition

Note that a function needs a return type. If the function does not return anything, that type must be void.