计算均值和方差

#include <iostream>
#include <boost/accumulators/accumulators.hpp>
#include <boost/accumulators/statistics/stats.hpp>
#include <boost/accumulators/statistics/mean.hpp>
#include <boost/accumulators/statistics/variance.hpp>
   
int main()
{
  using namespace boost::accumulators;
  accumulator_set<int, stats<tag::mean, tag::variance>> acc;

  for(int i = 1; i <= 6; i++)
    acc(i);

  std::cout << "mean=" << mean(acc) << ", variance=" << variance(acc) << '\n';
  // prints "mean=3.5, variance=2.91667"

  return 0;
}