无法访问在类“ CObject”中声明的私有成员

Question

I am trying to create a copy constructor for a CStringArray. once the code is compiled, visual studio gave me this error : Cannot access private member declared in class 'CObject'

in example.h I have declared the variable:

list<CStringArray>EqptListPpiedsOptions;

in example.cpp

I use this as my copy constructor :

example::example(const example &data) {
  list<CStringArray>::const_iterator itr = data.EqptListPpiedsOptions.begin();

  while (itr != data.EqptListPpiedsOptions.end()) {
    this->EqptListPpiedsOptions.push_back(*itr);
    itr++;
  }
}

How can I correctly use the copy constructor CStringArray List ?

Any help will be appreciated.

Answer 1

There's not much to say without knowing what CStringArray or EqptListPpiedsOptions are. But just as an aside:

If you're in C++11land or later, you can use auto instead of tediously spelling out the type, so

list<CStringArray>::const_iterator itr = data.EqptListPpiedsOptions.cbegin();

becomes

auto itr = data.EqptListPpiedsOptions.cbegin();

(Note also in C++11 you use cbegin() and cend() for const_iterator s.

And you can simplify further using ranged- for :

for (const auto &itr : data.EqptListPpiedsOptions) {
  this->EqptListPpiedsOptions.push_back(itr);
}

---

Here's a working example showing a copy constructor can access private data members of another instance of the class:

#include <initializer_list>
#include <iostream>
#include <list>

class Example {
public:
  Example() = default;
  Example(std::initializer_list<int> li) : li_(li) {}
  Example(const Example &data);
  void print() {
    for (const auto i : li_) {
      std::cout << i << ", ";
    }
  }

private:
  std::list<int> li_;
};

Example::Example(const Example &data) {
  for (const auto &i : data.li_) {
    this->li_.push_back(i);
  }
}

int main() {
  Example foo{5, 4, 3, 2, 1};
  Example bar;
  bar = foo; // call copy constructor and move foo.li_ to bar.li_
  bar.print();
}

Although in this example, the default copy constructor works just as well, so there's no need to specify a new one.