处理父/子类关系中的循环包含 [英] Dealing with circular inclusion in a parent/child class relationship

问题描述

假设我创建了一个类，例如 Parent ，它与 Child 具有组合关系。父类保存了一个子类的列表。

Assume I've made a class, say Parent, that has a composition relation with Child. The parent class holds a list of children.

我想让所有的子类保存对父类的引用，所以每个子类都拥有一个 code>指针。

I want all children to hold a reference to the parent, so every child holds a Parent pointer.

这将导致循环包含。我引用 parent.h 中的 Child ，我在中引用 Parent child.h 。因此 Parent 需要包括 Child ，需要包括 Parent

This will cause circular inclusion. I refer to Child in parent.h and I refer to Parent in child.h. Therefore Parent will need to include Child, which needs to include Parent.

推荐答案

p>您必须使用转发声明：

You'll have to use forward declaration:

//parent.h
class Child; //Forward declaration
class Parent
{
    vector<Child*> m_children;
};

//child.h
class Parent; //Forward declaration
class Child
{
    Parent* m_parent;
};

这篇关于处理父/子类关系中的循环包含的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！