安全地将（shared_ptr 到对象的向量）转换为（shared_ptr 到常量对象的向量）
class A {};
typedef shared_ptr<const A*> AConstPtr;
typedef shared_ptr<A*> APtr;
vector<APtr> ptr;
const vector<AConstPtr>* foo()
{
return &ptr;
}
此代码无法编译，因为“没有从向量<Aptr>*到const向量<AConstPtr
我需要这个的原因是因为我有一个类在内部将列表存储为矢量<APtr>，但需要通过公开它的完全const版本它的界面。
class A {};
typedef shared_ptr<const A*> AConstPtr;
typedef shared_ptr<A*> APtr;
vector<APtr> ptr;
const vector<AConstPtr>* foo()
{
return &ptr;
}
This code does not compile, because "there is no implicit conversion from vector<Aptr>* to const vector<AConstPtr> * "
Is there anyway to make this work, without creating a new vector, and without using an unsafe cast?
The reason why I need this is because I have a class that stores a list internally as vector<APtr>, but needs to expose a completely const version of it through its interface.
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由于不同的
shared_ptr不是相关类型，因此无法进行此类转换。首先，您真的确定需要公开存在共享指针的内部向量的实现细节吗？这确实会将您与该实现联系起来，并且在不破坏 API 的情况下不会对其进行更改。
使用 @Cubbi 的建议并让您的界面成为带有
begin和end方法的交互器怎么样？然后，您可以轻松地向外部客户端表示容器，而无需将自己绑定到vector。There's no way to do such a conversion since different
shared_ptrs aren't related types.First, are you really sure that you need to expose the implementation detail that there's an internal vector of shared pointers? That's really going to tie you to that implementation and it won't be subject to change without breaking API.
What about using @Cubbi's suggestion and having your interface be interators with
beginandendmethods instead? Then you can easily represent a container to the outside clients without tying yourself tovector.