c++11 double转string设置精度转换

#include <sstream>
#include <iomanip>

std::string to_string_with_precision(const double a_value,int precison)
{
    std::ostringstream out;
    out << std::fixed<<std::setprecision(precison) << a_value;
    return out.str();
}

    double persent = 0.12333;
    std::string ssss = to_string_with_precision(persent * 100,2); //"12.33"