Function FloatToString

contrib/libs/flatbuffers/include/flatbuffers/util.h:153–178

// Special versions for floats/doubles.
template<typename T> std::string FloatToString(T t, int precision) {
  // clang-format off

  #ifndef FLATBUFFERS_PREFER_PRINTF
    // to_string() prints different numbers of digits for floats depending on
    // platform and isn't available on Android, so we use stringstream
    std::stringstream ss;
    // Use std::fixed to suppress scientific notation.
    ss << std::fixed;
    // Default precision is 6, we want that to be higher for doubles.
    ss << std::setprecision(precision);
    ss << t;
    auto s = ss.str();
  #else // FLATBUFFERS_PREFER_PRINTF
    auto v = static_cast<double>(t);
    auto s = NumToStringImplWrapper(v, "%0.*f", precision);
  #endif // FLATBUFFERS_PREFER_PRINTF
  // clang-format on
  // Sadly, std::fixed turns "1" into "1.00000", so here we undo that.
  auto p = s.find_last_not_of('0');
  if (p != std::string::npos) {
    // Strip trailing zeroes. If it is a whole number, keep one zero.
    s.resize(p + (s[p] == '.' ? 2 : 1));
  }
  return s;
}

template<> inline std::string NumToString<double>(double t) {
  return FloatToString(t, 12);