#include <iostream>
#include <fstream>
#include <vector>
#include <cmath>

using namespace std;

void Mean(vector<double> &data, double &mean){
  for(unsigned int i=0; i<data.size(); i++){
    mean+=data.at(i);
  }
  mean=mean/(double)data.size();
}

void Deviation(vector<double> &data, double mean, double &sigma){
  for(unsigned int i=0; i<data.size(); i++){
    sigma+=pow((data.at(i)-mean), 2.0);
  }
  sigma=sigma/((double)data.size() - 1.0);
}

int main(){
  vector<double> data;
  double mean=0, sigma=0;  
  ifstream input("dane.dat");
  if(!input){
    cerr<<"Nie znaleziono pliku."<<endl;
    return 1;
  }

  while(!input.eof()){
    double tmp;
    input>>tmp;
    data.push_back(tmp);
  }
  input.close();
  
  Mean(data, mean);
  Deviation(data, mean, sigma);
  
  cout<<mean<<" +- "<<sigma<<" kOhm"<<endl;
  
  return 0;
}