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i is 8 and count is 2

i is 9 and count is 1

i is 10 and count is 0

The extern Storage Class
The extern storage class is used to give a reference of a global variable that is visible to
ALL the program files. When you use 'extern', the variable cannot be initialized, however, it
points the variable name at a storage location that has been previously defined.
When you have multiple files and you define a global variable or function, which will
also be used in other files, then extern will be used in another file to provide the reference of
defined variable or function. Just for understanding, extern is used to declare a global variable or
function in another file.
The extern modifier is most commonly used when there are two or more files sharing the
same global variables or functions as explained below.

First File: main.c

#include <stdio.h>

int count;

extern void write_extern();

main()
{

count = 5;
write_extern();

}

Second File: support.c

#include <stdio.h>

extern int count;

void write_extern(void)
{

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