Fstream作为私人会员访问

Question

File class

class File
{
private:
    fstream dataFile;

public:
    File();
};

File::File()
{
    dataFile.open("Morse.bin", ios::in | ios::binary);
    if(dataFile.fail())
        cout << "File could not be opened.\n";
    else
        cout << "File opened successfully!\n";
}

Decoder class

class Decoder: public File
{
private:
    char line;

public:
    void getLine();
};

void Decoder::getLine()
{
    while(dataFile.get(line))
    {
       cout << line;
    }
}

2 Questions:

1. Does dataFile contain the Morse.bin contents? The file opened successfully message shows up, but I just want to make sure.

2. I want to read a character by character from in the Decoder class. The issue I am having is accessing the dataFile from the Decoder class. I tried creating a accessor function for the dataFile but it won't allow me to access it. The error messages is that File::dataFile is inaccessible . Which make sense because it is private. However, if I can't create a accessor function which would return dataFile , how do I get a hold of dataFile in order the manipulate it?

Answer 1

1. Not yet. You haven't read from it.

2. Make dataFile protected, or provide an accessor to it from File .

    class File { protected: fstream dataFile; public: File(); }; File::File() { dataFile.open("Morse.bin", ios::in | ios::binary); if(dataFile.fail()) cout << "File could not be opened.\\n"; else cout << "File opened successfully!\\n"; }