convert.cpp

class ConverterInterface {
   void WriteInt(int, int);
   void WriteDouble(int, double);
}

void convert_stream(Stream stream, ConverterInterface *writer) {
    for (auto record : stream) {
        if (record.type == INT) {
            writer->WriteInt(record.fieldnumber, record.intvalue);
        } else if (record.type == DOUBLE) {
            writer->WriteDouble(record.fieldnumber, record.intvalue);
        } 
    }
}