I have this code to read doubles from a file:

int main() {
  ofstream out("output.txt");
  out << "3.0x1.5y-2.0z0.5" << endl;
  out.close();
  ifstream in("output.txt");
  while (true) {
    double x;
    in >> x;
    if (in.eof())
      break;
    if (x) { // got a double
      cout << x << endl;
    } else { // skip invalid char
      in.clear();
      in.ignore(1);
    }
  }
  return 0;
}

The problem is that x is taking unexpected values. Why does it read 5, -2 and 0.5 for file with content “3.0×1.5y-2.0z0.5” instead of 3.0, 1.5, -2 and 0.5?