Scope of a variable outside main in C

Question

Consider the code:

#include 

int x;

int main (void) 
{ }

The value of x is 0 inside main

Answer 1

x is a global variable, it has space allocated for it when the program starts and is initialized to 0 (generally, however you should have an explicit initializer).

The 'static' keyword has two different meanings.

1)

static int x;

int main() { }

This limits the scope of x to the single file. Although it is still a global variable, the linker will not be able to connect references to x from other files.

2)

int main() {
   static int x;
}

This effectively turns x into a global variable. Although the scope is still within the main function, space is allocated for it globally, and it's value will be retained between calls to main().