#include <iostream>
#include <iomanip>
#include <cmath>
#include <cstdlib> //contiene la dichiarazione  di rand()
using namespace std;

  double mean =0;
  double variance =0;
  double scarto =0;

int main () {
  int sampleSize;
  cout << "Digita quandi numeri casuali bisogna generare" << endl;
  cin >> sampleSize; 

  double * sample = new double[sampleSize];
  for (int n = 0; n < sampleSize; n++){
  sample[n] = (double) random() / (double) RAND_MAX;
 }

  //calcola la media

  for (int n = 0; n < sampleSize; n++){
    mean += sample[n];
  }
  mean /= (double) sampleSize;

  //calcola la varianza

  for( int n = 0; n < sampleSize; n++){
    scarto = sample[n] - mean;
    scarto *= scarto;
    variance += scarto;
  }
  variance  /= (double) sampleSize;

  // calcolo la deviazione standard
  double stddev = sqrt(variance);

  //risultato
  cout << "media =" << mean <<"; varianza = " << variance << "; deviazione standard = " << stddev << endl;
  delete [] sample;
  return (0);

}