c++在通知父级的同时删除树结构中的所有子级

Question

考虑到这一点:

class A {    
public:
     A()
    ~A()
     void add(A *child);
     void remove(A *child);
     void set_parent(A *parent);
private:
     A *parent;
     std::list<A*> children;
};

add、remove 和 set_parent 显然可以访问列表或父属性。

通过以下实现:

A::A() : parent(nullptr){};
A::~A() {
    //Keep the hierarchy clean and inform parent that we are gone now
    if(this->parent != nullptr) {
        this->parent->remove(this);
    }
    //Also delete all children as they would be lost now ...
    for(A *child : children) {
        delete child;
    }
}
void A::set_parent(A *parent)
{
    if(this->parent != nullptr)
        this->parent->remove(this);
    this->parent = parent;
}

我实际上不想做任何更复杂的事情，但问题是，当删除列表的子级时，他们每个人都会通知他们的父级他们现在不在了，从而操纵我们当前正在迭代的列表。可以做什么？

Answer 1

在删除子项之前“分离”父项怎么样？

A::~A() {
    //Keep the hierarchy clean and inform parent that we are gone now
    if(this->parent != nullptr) {
        this->parent->remove(this);
    }
    //Also delete all children as they would be lost now ...
    for(A *child : children) {
        child->set_parent(nullptr); // Detach parent to avoid re-calling remove()
        delete child;
    }
}