C++11随机数等.cpp

C++11随机数等.cpp

#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <iterator>
#include <random>



int main()
{
  //std::copy(v.begin(),v.end(),std::ostream_iterator<string>(std::cout, "\n"));
  
  std::default_random_engine generator;
  //std::normal_distribution<double> distribution(5.0,1.0);
  std::uniform_real_distribution<double> distribution(0.1,1.0);

  std::vector<double> res;
  for(int i=0;i<30;++i){
    res.push_back(distribution(generator));
  }
  for(int i=3 ;i<30;++i){
    //res[i] += 100.0;
  }
  
  std::sort(res.begin(),res.end());
  std::copy(res.begin(),res.end(),std::ostream_iterator<double>(std::cout, ","));
  std::cout<<std::endl;
  
  std::pair<std::vector<double>::const_iterator,std::vector<double>::const_iterator> maxmin 
           = std::minmax_element (res.begin(),res.end());
  double min = *maxmin.first;
  double max = *maxmin.second;
  std::cout<<"max:"<<max<<"  min:"<<min;
  
  int fc[10] = {0,0,0,0,0,0,0,0,0,0};
  double sum = 0.0;
  for(auto& r:res){
    int i = ((r - min) * 9.99) /(max - min);
    fc[i] += 1;
    sum += r;
  }
  std::cout<<"  avg:"<<sum/res.size()<<std::endl;
  
  std::copy(std::begin(fc),std::end(fc),std::ostream_iterator<int>(std::cout, "|"));
  std::cout<<"\n(max - min) = "<<(max - min)<<std::endl;
  
  double rs = 0.0;
  for(auto& r:res){
    int i = ((r - min) * 9.99) /(max - min);
    rs += 1.0/r /double(fc[i]);
  }
  rs /= 30;
  rs = 1.0/rs;
  
  std::cout<<"rs = "<<rs<<std::endl;
  return 0;
}