How can I format a number when emitting using yaml-cpp?

I need to output my data in scientific notation with fixed width like the sample below. Is there any way to achieve it?

data:

- [+0.000000e+00, +0.100000e+00, +2.400000e+00, +3.600000e+00, +4.800000e+00]

- [+1.开发者_运维百科200000e+00, +1.300000e+00, +2.400000e+00, +4.800000e+00, +6.000000e+00]

-SW

Make a wrapper class for your data:

struct Fixed {
   Fixed(double v = 0): value(v) {}
   double value;

   std::string ToString() const {
      /* write something that outputs this in the format you want */
   }
};

and overload operator <<:

YAML::Emitter& operator << (YAML::Emitter& out, const Fixed& f) {
   out << f.ToString();
   return out;
}

Then it'll work as you'd expect:

std::vector<Fixed> data = /* ... */;
YAML::Emitter out;
out << data;  // etc