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