public static string formatForWrite(Student stIn) { if (stIn is FullTimeStudent) { FullTimeStudent fts = (FullTimeStudent)stIn; return($"F#{fts.getId()}#{fts.getFirstName()}#{fts.getLastName()}#{fts.getCampus()}"); } else if (stIn is DistanceStudent) { DistanceStudent dts = (DistanceStudent)stIn; return($"D#{dts.getId()}#{dts.getFirstName()}#{dts.getLastName()}#{dts.getFacilitator()}"); } else { return($"E#{stIn.getId()}"); } }