int g1, g2;voidwrite_at (addr, off, val)     int *addr;     int off;     int val;{  g2 = 1;  addr[off] = val;  g2++;}main (){  g2 = 12;  write_at (&g1, &g2 - &g1, 12345);  printf ("%d\n", g2);}