通过重置类析构函数中的成员shared_ptrs来解决C++11 shared_ptr循环引用？

class B;  // 前向声明

class A {
public:
    A() {
        std::cout << "A constructor" << std::endl;
    }

    ~A() {
        std::cout << "A destructor" << std::endl;
        b_ptr.reset();  // 重置指向类B的shared_ptr
    }

    void setB(std::shared_ptr<B> b) {
        b_ptr = b;
    }

private:
    std::shared_ptr<B> b_ptr;
};

class B {
public:
    B() {
        std::cout << "B constructor" << std::endl;
    }

    ~B() {
        std::cout << "B destructor" << std::endl;
        a_ptr.reset();  // 重置指向类A的shared_ptr
    }

    void setA(std::shared_ptr<A> a) {
        a_ptr = a;
    }

private:
    std::shared_ptr<A> a_ptr;
};

int main() {
    std::shared_ptr<A> a = std::make_shared<A>();
    std::shared_ptr<B> b = std::make_shared<B>();

    a->setB(b);
    b->setA(a);

    return 0;
}