16     static int count;  member
18     explicit B(int id) : id_(id) {count++;}  in B()
19     B(const B& a) : id_(a.id_) {count++;}  in B()
20     ~B() {count--;}  in ~B()
23 int B::count = 0;  member in B
28     static int count;  member
30     explicit A(int id) : B(id-1), id_(id) {count++;}  in A()
31     A(const A& a) : B(a.id_-1), id_(a.id_) {count++;}  in A()
32     ~A() {count--;}  in ~A()
35 int A::count = 0;  member in A
39     assert(A::count == 0);  in f1()
40     assert(B::count == 0);  in f1()
42     assert(A::count == 1);  in f1()
43     assert(B::count == 1);  in f1()
52         assert(A::count == 0);  in f2()
58         assert(A::count != 0);  in f2()
59         assert(B::count != 0);  in f2()
78         assert(B::count != 0);  in main()
81     assert(A::count == 0);  in main()
82     assert(B::count == 0);  in main()