1  extern void abort (void);
       2  extern void exit (int);
       3  
       4  main()
       5  {
       6      int a,b,c;
       7      int *pa, *pb, *pc;
       8      int **ppa, **ppb, **ppc;
       9      int i,j,k,x,y,z;
      10  
      11      a = 10;
      12      b = 20;
      13      c = 30;
      14      pa = &a; pb = &b; pc = &c;
      15      ppa = &pa; ppb = &pb; ppc = &pc;
      16      x = 0; y = 0; z = 0;
      17  
      18      for(i=0;i<10;i++){
      19          if( pa == &a ) pa = &b;
      20          else pa = &a;
      21          while( (*pa)-- ){
      22              x++;
      23              if( (*pa) < 3 ) break;
      24              else pa = &b;
      25          }
      26          x++;
      27          pa = &b;
      28      }
      29  
      30      if ((*pa) != -5 || (*pb) != -5 || x != 43)
      31        abort ();
      32  
      33      exit (0);
      34  }