There is no "right way". If you want a universal (but suboptimal) solution you can use a boost::lexical cast.
A common solution for C++ is to use std::ostream and << operator. You can use a stringstream and stringstream::str() method for conversion to string.
If you really require a fast mechanism (remember the 20/80 rule) you can look for a "dedicated" solution like C++ String Toolkit Library
Best Regards,
Marcin
