#include <stdio.h>

int main(void)
{
   int    a = 1;
   void   try_to_change_it(int);

   printf("%d\n", a);     /* 1 is printed */
   try_to_change_it(a);
   printf("%d\n", a);     /* 1 is printed again! */
   return 0;
}

void try_to_change_it(int a)
{
   a = 777;
}