矢量迭代铸造 [英] Vector Iterators Casting

问题描述

嘿，在C ++中，我有一个类型的向量：

Hey, In C++, I have a vector of type:

vector<BaseClass*> myVector;

其中，我插入（push_back）派生类的指针。

In which, I insert (push_back) pointers of derived classes into it.

现在，我想弹出它的元素，所以我这样做：

Now, I want to pop back its elements so I do this:

vector<ADlgcDev*>::iterator iter;

for (iter = myVector.rbegin(); iter != myVector.rend(); iter++)
{
 // but before I pop it, I need to shutdown it down
 // so I cast this
 // but this way, I'm unable to call the function
 (DerivedClass*(*iter))->Shutdown();

 myVector.pop_back();
}

但是在我弹出之前的注释中，我需要调用它关闭（）方法，投射也无法正常工作。任何决议？或者不可能？

but as mention in the comments before I pop it, I need to call its Shutdown() method and the cast is not working properly too. Any resolutions? or is impossible?

推荐答案

while (!myVector.empty())
{
  ((DerivedClass*)(myVector.back()))->Shutdown();
  myVector.pop_back();
}

注意：

• 您应该使用 dynamic_cast 而不是强制转换。 （如果确定向量中只有 DerivedClass 对象，为什么不是 std :: vector< DerivedClass> ？）


• 你可能不需要强制转换，因为 Shutdown（）应该在基类中声明。


• 您应该也可以删除对象，然后将其从向量中弹出。


• 你应该使用一个智能指针调用 Shutdown（）（和 delete ，可能）。

• You should probably use dynamic_cast instead of the hard cast. (If it's sure that there are only DerivedClass objects in the vector, why isn't it std::vector<DerivedClass>?)
• You should probably not have to cast at all, since Shutdown() should be declared in the base class.
• You should probably delete the objects, too, before you pop them off the vector. (But that might not be so.)
• You should probably use a smart pointer which calls Shutdown() (and delete, probably).

编辑：使用 std :: vector< T> :: clear ），如markh44 所示可能比 pop_back（）。

Using std::vector<T>::clear(), as shown by markh44 is probably better than the pop_back().

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