When using command line arguments, is better to use them as c strings and interact with them using the cstring header functions?, or is better to convert them to library strings for using them?

im new in c++ and i am creating a version of cat for practicing what i have learned so far. What im doing for managing the command line arguments is converting them to library strings and then using them, but now i have the doubt if it is the correct / most optimal way to do it