How to avoid if fstream opens a directory (infinite loop)?

[nianqing]

If the filename below is a directory, then the following loop goes to infinite.

std::ifstream in;
in.open(filename, std::ifstream::in);
if(in.fail()) return;
if (in.bad()) return;
if (in.good()) {
int i;
while (!in.eof()) {
std::string sLine;
std::getline(in, sLine);
std::cout << i++ << "\t" << sLine << std::endl;
}
}

[Cubbi]

Just don't use while (!in.eof()). Check the result of getline() instead: while(getline(in, sLine) { ...