Stringstream skipping first line

[MrPickle]

I have a tag like so:
<foo>

and I am trying to extract 'foo' from this.
I'm using a stringstream in a while loop but it seems to fail with the first line, then it works with every other line.

std::ifstream is("xml.txt");
    if(is.fail())
    {
        return 0;
    }
    std::string str, tag;
    std::stringstream ss;
 
    while(std::getline(is, str))
    {
        tag = "";
        ss.seekg(std::stringstream::beg);
        ss.str(str);
        ss.ignore(256, '<');
        ss >> tag;
        std::cout << ss.str()<< " " << tag << "\n";
    }

[JosAH]

What happens when you swap lines #12 and #13?

kind regards,

Jos

[MrPickle]

It works O_O

Why does this make a difference?

[JosAH]

@MrPickle

The first time through the loop your stringstream has no string set to move to the begin of; it sets the stringstream to a fail status. After swapping those two lines it does have a string so it can move to the begin position thereof.

I don't know by head if setting a new string makes the stream moves to its begin position; check it out; if it does you can remove that seekg alltogether.

kind regards,

Jos