(C++) Overloading the divide-equals operator

include <iostream>

include <vector>

class TimePoint
{
  public:
  TimePoint() { reset(); }
  double mean;
  double stdDev;
  void reset()
  {
    mean = 0;
    stdDev = 0;
  }
  void operator/=(const double& value)
  {
    mean/=value;
    stdDev/=value;
  }
};
TimePoint getAverage(const std::vector<TimePoint>& timePoints)
{
  TimePoint result;
  const int nTimePoints = timePoints.size();
  for (int i=0; i<nTimePoints; ++i)
  {
    result.mean+=timePoints[i].mean;
    result.stdDev+=timePoints[i].stdDev;
  }
  result/=static_cast<double>(nTimePoints);
  return result;
}

int main()
{
  const int nTimePoints = 10;
  std::vector<TimePoint> timePoints(nTimePoints);
  for (int i=0; i<nTimePoints; ++i)
  {
    timePoints[i].mean = static_cast<double>(i);
    timePoints[i].stdDev = 1.0;
  }
  const TimePoint averageTimePoint = getAverage(timePoints);
  std::cout << "averageTimePoint.mean: " << averageTimePoint.mean << std::endl;;
  std::cout << "averageTimePoint.stdDev: " << averageTimePoint.stdDev << std::endl;
  return 0;
}

include <iostream>

include <vector>


class TimePoint
{
  public:
  TimePoint() { reset(); }
  double mean;
  double stdDev;
  void reset()
  {
    mean = 0;
    stdDev = 0;
  }
  void operator/=(const double& value)
  {
    mean/=value;
    stdDev/=value;
  }
  void operator+=(const TimePoint& timePoint)
  {
    mean+=timePoint.mean;
    stdDev+=timePoint.stdDev;
  }
  friend std::ostream& operator<<(
    std::ostream& os, 
    const TimePoint& timePoint)
  {
    os << "timePoint.mean: " << timePoint.mean
       << '\t' << "timePoint.stdDev: " << timePoint.stdDev;
    return os;
  }
};
TimePoint getAverage(const std::vector<TimePoint>& timePoints)
{
  TimePoint result;
  const int nTimePoints = timePoints.size();
  for (int i=0; i<nTimePoints; ++i)
  {
    result+=timePoints[i];
  }
  result/=static_cast<double>(nTimePoints);
  return result;
}

int main()
{
  const int nTimePoints = 10;
  std::vector<TimePoint> timePoints(nTimePoints);
  for (int i=0; i<nTimePoints; ++i)
  {
    timePoints[i].mean = static_cast<double>(i);
    timePoints[i].stdDev = 1.0;
  }
  const TimePoint averageTimePoint = getAverage(timePoints);
  std::cout << averageTimePoint << std::endl;
  return 0;
}