stringstream operator input failing

Question

What is wrong with this overloaded operator?

I am trying to parse a stringstream to an object which has the members a , b and c as integers.

istream& operator>> (istream& in, Feedback& object) {
    cout << __PRETTY_FUNCTION__ << endl;
    in >> object.a;
    in >> object.b;
    in >> object.c;
    cout << object.a << " " << object.b << " " << object.c << endl;
    return in;
}

The last cout is printing 0 for all members.

I can see that the stringstream is properly filled before the input operator in this code...

cout << __PRETTY_FUNCTION__ << ": " << ss.str().c_str() << endl;
ss >> feedback;

this cout prints:

Feedback parseFeedbackData(unsigned char*, int): 10 2 4

The output overloaded operator is working fine. You can find the code below:

ostream& operator<< (ostream& out, Feedback& object) {
    cout << __PRETTY_FUNCTION__ << endl;
    out << object.a << " " << object.b << " " << object.c;
    return out;
}

Answer 1

The output of ss.str().c_str() does not necessarily give a clue as to what the other states of the istringstream object are.

You should add tests to make sure that the reads are successful.

istream& operator>> (istream& in, Feedback& object) {
    cout << __PRETTY_FUNCTION__ << endl;

    if ( !(in >> object.a) )
    {
       cout << "Problem reading a\n";
       return in;
    }

    if ( !(in >> object.b) )
    {
       cout << "Problem reading b\n";
       return in;
    }

    if ( !(in >> object.c) )
    {
       cout << "Problem reading c\n";
       return in;
    }

    cout << object.a << " " << object.b << " " << object.c << endl;
    return in;
}

This will help you figure out where the problem lies.