指针和指针在C ++中的集合。如何正确删除 [英] Pointers and collection of pointers in C++. How to properly delete

问题描述

这是一个新的问题，但我已经用C指针的alwasy怀疑。这是情况。

This is a newbe question but I have alwasy doubts with pointers in C++. This is the situation.

我有一个类A作为类B的指针的集合（实际上是一个向量）。同一个类A有另一个指针集合最后，类B的对象还有一个指向类C的指针的集合，指向类A指向的相同实例。

I have a class A which as a collection (a vector actually) of pointers of class B. This same class A has another collection of pointers to class C. Finally the objects of class B have also a collection to pointers to class C which point to the same instances the class A points to.

我的问题是，如果我在类B中删除了类C类型指针的成员，类A中指向类C的删除实例的指针发生了什么？这种情况如何处理？

My question is, if I delete a member of class-C-type pointer in class B, what happens to the pointer in class A that points to the deleted instance of class C? How this situation has to be treated?

非常感谢！

Julen。

推荐答案

我的理解：

A
 - vector<B*>
 - vector<C*>

B
 - vector<C*>

从B中删除所有的C *。

From within B you are deleting all of the C*.

您需要单独删除每个内存地址，但最多只能删除一次。

You need to delete each memory address separately, but only at most once.

任何指向已删除地址的指针仍然拥有相同的地址，如果您使用它，它只会产生未定义的行为。

Any pointer to a deleted address is still holding the same address, it just produces undefined behavior if you use it.

因此，请务必不要从已删除的A中重新删除B *，并确保在删除之后不要使用它们。

So be sure not to re-delete the B* from A that you already deleted, and be sure not to use them after they are deleted.

您可能想重新考虑您的层次结构/设计。

You may want to re-consider your hierarchy/design though.

或考虑使用 boost :: shared_ptr 如果你需要以这种方式存储的东西。实际上，只要你存储指针的集合，你应该使用boost :: shared_ptr。如果你使用boost :: shared_ptr，你不会删除，你不需要担心使其他指针无效。

Or consider using boost::shared_ptr if you need to store things in this way. Actually anytime you're storing a collection of pointers you should probably be using boost::shared_ptr. If you are using boost::shared_ptr you don't delete and you don't need to worry about invalidating the other pointers.

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