[Dev] Fixed a compilation bug: an input file, i.e., std::ifstream, should be tested thanks to the is_open() method, not directly.
[Dev] Fixed a compilation bug: an input file, i.e., std::ifstream, should be tested thanks to the is_open() method, not directly.

airsim/airrac,airsim/airrac,jwakely/airrac,airsim/airrac,jwakely/airrac,jwakely/airrac