错误C2248：无法访问在类中声明的私有成员

Question

I have creates this class:

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

class XLSCreator
{
private:
    ofstream filecontents;
    int fileType;
    int cellNumber;
    int rowsNumber;
public:
    XLSCreator(string);
    ~XLSCreator();
    void createType1File(string, string, string);
    void createType2File(string, string, string, string, string);
    void addNewRow();
    void addData(string);
    void saveFile();
};

But When I tried to build it, it gave me this error:

Error 2 error C2248: 'std::basic_ofstream<_Elem,_Traits>::basic_ofstream' : cannot access private member declared in class 'std::basic_ofstream<_Elem,_Traits>'

So can anybody help me with this?

Answer 1

The error you describe could not have come from the code you have provided; your class declaration is fine. It must have come from a different part of your code, in which you attempted to copy your XLSCreator class, eg by invoking copy-assignment:

XLSCreator foo("filename");
XLSCreator bar = foo; //copies foo to create bar

The error arises when C++ attempts to generate a default copy-assignment operator for your class, which simply calls the copy-assignment operator of each member you've declared. std::ofstream is non-copyable, as @chris said in the comments, so when the compiler attempts to call the copy assignment operator of filecontents , it finds that it's not allowed to ( operator= is private within basic_ofstream ).

In order to fix this, you either need to ensure you never copy an XLSCreator , or explicitly define a copy-assignment operator for XLSCreator that somehow handles the filecontents member without attempting to copy it.

Answer 2

Don't you need to import ofstream? I don't think you can create ofstreams with just iostream and fstream.