具有私有拷贝构造函数的类的C ++ stl向量？

Question

There is a class in our code, say class C . I want to create a vector of objects of class C . However, both the copy constructor and assignment operator are purposely declared to be private . I don't want to (and perhaps am not allowed) to change that.

Is there any other clean way to use/define vector<C> ?

Answer 1

您可以使用vector<C*>或vector<shared_ptr<C>> 。

Answer 2

I have managed to do it by using just two friends:

template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
    friend class std::vector;
template<typename _T1, typename _T2>
    friend void std::_Construct(_T1* __p, const _T2& __value);

Put them inside your class declaration and voila!

I am using gcc 5.3.1.

Answer 3

You may use move constructor here.

#include<iostream>
#include<vector>

class Road
{
   Road(const Road& obj){}                            //copy constructor
   Road& operator=(const Road& obj){ return *this; }  //copy assignment

   public:
   /*May use below commented code as well
     Road(const Road&)=delete;
     Road& operator=(const Road&)=delete;
   */

   Road()=default;                                    //default constructor
   Road(Road&& obj){}                                 //move constructor
   void display(){ std::cout<<"Object from myvec!\n"; }
};

int main()
{
   std::vector<Road> myVec;
   Road obj;
   myVec.push_back(std::move(obj));

   myVec[0].display();
   return 0;
}

Answer 4

Do you have access to the boost library ?

Create a vector of boost shared pointers .

   std::vector<boost:shared_ptr<C>>

Answer 5

No, it isn't, std::vector requires assignable concept. The authors of C must have had a good reason to prohibit this, you have to stick with whatever they provide to copy/assign instances of C . Either you use pointers as suggested above, or C provides other mechanism to copy/assign itself. In the latter case you could write an assignable proxy type for C .