Error handling inside overloaded >>

A class... field has the following types of members :

Code:

        int index;
        std::string name;
        std::string type;
        bool p_key;
        bool c_key;

I'm asking it to handle inputs of the following format:
[Int,String1,String2,Bool1,Bool2]
//The bools seem to be automatically stored and retrieved as o and 1

So..in the following code...
What do I put in /*Error*/ ?
Also, when an unexpected type of input goes through, is it sufficient to return the istream object in its fail state ?

Code:

    std::istream& operator>>(std::istream& is,field& f)
    {
        char c;
        is>>c;if(c!='['){/*Error*/};
        is>>f.index;
        is>>c;if(c!=','){/*Error*/};
        std::getline(is,f.name,',');
//         is>>c;if(c!=','){/*Error*/}else is.unget(); //Wrong
        std::getline(is,f.type,',');
//         is>>c;if(c!=','){/*Error*/}else is.unget(); //Wrong
        is>>f.p_key;
        is>>c;if(c!=','){/*Error*/};
        is>>f.c_key;
        is>>c;if(c!=']'){/*Error*/};
        return is;
    }

Originally Posted by manasij7479

What do I put in /*Error*/ ?
Also, when an unexpected type of input goes through, is it sufficient to return the istream object in its fail state ?

That's one way of reporting the problem: simply return the stream when you detect a read error.

Originally Posted by laserlight

That's one way of reporting the problem: simply return the stream when you detect a read error.

And when a read error isn't there....like in the 1st,2nd,5th && 6th ..checks ....do I have to force the stream into such a state ?
Which bit(?) do I need to set ? ...if I later determine by success by something like if(cin>>object) ?

do I have to force the stream into such a state ?
Which bit(?) do I need to set ?

Looks like you can do something along the lines of:

Code:

is.clear(std::ios_base::badbit);

You mean
is.set(...);
?

Well, I looked up "set stream state" on the interweb and what came back suggested using clear (which I thought was odd but the page I linked to says it also sets the state). I also tested it and it worked so that's what I went with. Maybe setstate would work as well?

void clear ( iostate state = goodbit );

Set error state flags
Sets a new value for the error control state.

void setstate ( iostate state );

Set error state flag
Modifies the current error state value by combining (like with a bitwise OR operation) the error state flags passed as argument with those currently set for the stream.

Any error bitflag already set is not cleared. If you want to modify the state flags without keeping the current value, use clear() instead.