extern and global in c
- by JPro
Can anyone please tell me is there any special requirement to use either EXTERN or GLOBAL variables in a C program?
I do not see any difference in a program like below, if I change from gloabl to extern.
#include <stdio.h>
#include <stdlib.h>
int myGlobalvar = 10;
int main(int argc, char *argv[])
{
int myFunc(int);
int i;
i = 12;
myGlobalvar = 100;
printf("Value of myGlobalvar is %d , i = %d\n", myGlobalvar, i);
i = myFunc(10);
printf("Value of passed value : %d\n",i);
printf("again Value of myGlobalvar is %d , i = %d\n", myGlobalvar, i);
system("PAUSE");
return 0;
}
int myFunc(int i)
{
i = 20 + 1000;
//extern int myGlobalvar;
myGlobalvar = 20000;
// printf("Value of passed value : %d",i);
return i;
}
If uncomment extern int myGlobalvar, the value does not change.
Is there any correct difference between both?
Can anyone please correct me?
