What's the difference between std::to_string, boost::to_string, and boost::lexical_cast?

Question

What\'s the purpose of boost::to_string (found in boost/exception/to_string.hpp) and how does it differ from boost::lexical_cast

Answer 1

There are more differences: boost::lexical_cast works a bit different when converting double to string. Please consider the following code:

#include 
#include 

#include "boost/lexical_cast.hpp"

int main()
{
    double maxDouble = std::numeric_limits::max();
    std::string str(std::to_string(maxDouble));

    std::cout << "std::to_string(" << maxDouble << ") == " << str << std::endl;
    std::cout << "boost::lexical_cast(" << maxDouble << ") == "
              << boost::lexical_cast(maxDouble) << std::endl;

    return 0;
}

Results

$ ./to_string
std::to_string(1.79769e+308) == 179769313486231570814527423731704356798070600000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000
boost::lexical_cast(1.79769e+308) == 1.7976931348623157e+308

As you can see, the boost version uses exponential notation (1.7976931348623157e+308) whereas std::to_string prints every digit, and six decimal places. One may be more useful than another for your purposes. I personally find the boost version more readable.