1  extern int lookup1 (int i);
       2  extern int lookup2 (int i);
       3  extern void abort (void);
       4  
       5  int lookup3 (int i)
       6  {
       7    int a[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
       8    return a[i+2];
       9  }
      10  
      11  int main (void)
      12  {
      13    if (lookup1(2) != 2)
      14      abort ();
      15  
      16    if (lookup2(2) != 3)
      17      abort ();
      18  
      19    if (lookup3(2) != 4)
      20      abort ();
      21  
      22    return 0;
      23  }