Get input from command line and store to a file

int main(int argc, char **argv) {
  if(argc < 2) {
    cout << "Please pass the file name to write to" << endl;
    return -1;
  }
  string filename = argv[1];

  ofstream out(filename);
  if(!out) {
    cerr << "Cannot open file " << filename << endl;
    return -1;
  }
  string line;
  while(getline(cin, line)) {
    out << line << endl;
  }
  out.close();
  return 0;
}