I'm not really sure how I feel about the way we print the headers in this file. I just found this, which I think we can use to print the headers:

```
std::ostream_iterator<std::string> print_headers (s, ",");
std::copy (val.begin(), val.end(), print_headers );
``` 
Link: http://www.cplusplus.com/reference/iterator/ostream_iterator/

Take a look