C++构造函数与析构函数的调用顺序

using namespace std;

class A
{
public:
A() { cout << "A is created!" << endl; }
~A() { cout << "A is destroyed!" << endl; }
};
class B
{
public:
B() { cout << "B is created!" << endl; }
~B() { cout << "B is destroyed!" << endl; }
};
class C
{
public:
C() { cout << "C is created!" << endl; }
~C() { cout << "C is destroyed!" << endl; }
};

class D : public C
{
B b;
A a;
public:
D():a(), b() { cout << "D is created!" << endl; }
~D() { cout << "D is destroyed!" << endl; }
};
int main(int argc, char* argv[])
{
D d;
}

C is created!
B is created!
A is created!
D is created!
D is destroyed!
A is destroyed!
B is destroyed!
C is destroyed!