#include <iostream>
#include <cmath>
#include <fstream>
#include <iomanip>
using namespace std;
      
const int MAXSIZE = 1000;
   
    
      
    
/**
* computes the maximum and minimum values in the data set
* @param data - an array containing the measurements
* @param count - the number of measurements
* @param min - the minimum measurement
* @param max - the maximum measurement
*/  
         
   void minMax(const double data [ ], int count, double& min, double& max)
   {
   min = data[0];
   for(count = 0; count<MAXSIZE;)
   {
      count++;
   }
   if (data[count] < min)
   {
      min = data[count];
   }
   max = data[0];
   for(count=0; count<MAXSIZE;)
   {
      count++;
   }
   if(data[count] > max)
   {
         max = data[count];
   }
   double range = max - min;
   cout<<"Min: " <<setprecision(4)<<setw(20)<<min;
   cout<<"Max: " <<setprecision(4)<<setw(20)<<max;
   cout<<"range: " <<setprecision(4)<<setw(18)<<range;
   /**
* computes the sample mean
* @param data - an array containing the measurements
* @param count - the number of measurements
* @return the mean of the set of measurements
*/

   double calcMean(const double data[ ], int count)
   {
   double sum = 0;
   double mean;
   int i;
      for(i = 0; i < count; i++);
      {
      sum += data[i];
      mean = sum/count;
      }
   return mean;
}
/**
* computes the sample variance
* @param data - an array containing the measurements
* @param count - the number of measurements
* @return the sample variance of the set of measurements
*/

   double calcVariance(const double data[ ], int count)
   {
   double sum = 0;
   double var = 0;
   double mean;
   int i;
      for(i = 0; i < count; i++);
      {
      sum += data[i];
      mean = sum/count;
      var = pow(data[i]-mean,2);
   }
    return var;
}

int main()
{
   double data[MAXSIZE];
   double range, mean, variance, stand_dev;
   string file;
   int count;
   cout<<"Enter the name of the data file>"<<endl;
   cin>>file;
   cout<<endl;
   cout<<"Descriptive Statistics"<<endl;
   cout<<"------------------------------"<<endl;


   ifstream inputFile;
   inputFile.open("sewage.data");
   if(!inputFile)
   {
      cout<<"error opening File."<<endl;
   }
   while(count = 0,count < MAXSIZE && inputFile >> data[count])
   {
      count++;
   }
    cout<<"N: "<<setw(22);
    cin>>count;
    minMax(data, count, min, max);
    cout<<"range: " <<setprecision(4)<<setw(18);
    mean = calcMean(data, count);
    cout<<"mean:"<<setprecision(4)<<setw<<(19)<<mean<<endl;
    variance = calcVariance(data, count);
    cout<<"variance:"<<setw(15)<<setprecision<<(4)<<variance<<endl;
    stand_dev = sqrt(variance);
    cout<<"Standard Deviation: "<<setw(6)<<setprecision(4)<<stand_dev<<endl;
    inputFile.close();
      return 0;
}