Can't declare ifstream class member in header file

Question

I am trying to declare an ifstream object in a header file as is shown but I get an error saying that it cannot be accessed. I have tried various things such as making it into a pointer instead, initialising in the .c file etc. but my code can't seem to get part the declaration of it. ReadFile.h: ``` #ifndef READFILE_H #define READFILE_H #include "cv.h" #include "highgui.h" #include #include class ReadFile{ private: std::ifstream stream; public: std::string read(); ReadFile(); // Default constructor ~ReadFile(); // Destructor }; #endif ``` ReadFile.c: #include "ReadFile.h" ``` ReadFile::ReadFile(){ stream.open("./data.txt"); } ReadFile::~ReadFile(){ stream.close(); } ``` The error that I am getting is: ``` Error 9 error C2248: 'std::basic_ifstream<_Elem,_Traits>::basic_ifstream' : cannot access private member declared in class 'std::basic_ifstream<_Elem,_Traits>' c:\users\Bob\documents\project\models\readfile.h 23 1 Project ``` The output is: ``` 1>c:\users\Bob\do…

Accepted Answer

The problem is that `std::ifstream` doesn't have a public copy constructor (because copying one wouldn't make sense) but the compiler-generated copy constructor for your class wants to use it.

It doesn't have any available assignment operator for the same reason (i.e. copying a `std::ifstream` is nonsense).

You should disallow copying and assignment for your class as well.

A simple way is to add

```
private:
    ReadFile(const ReadFile&);
    ReadFile& operator=(const ReadFile&);
```

to your class, if you're using C++03.

In C++11, use the `= delete` syntax.

```
public:
    ReadFile(const ReadFile&) = delete;
    ReadFile& operator=(const ReadFile&) = delete;
```

Can't declare ifstream class member in header file

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