diff --git a/homework2/plot.py b/homework2/plot.py
index 8af1a89..2ed038a 100644
--- a/homework2/plot.py
+++ b/homework2/plot.py
@@ -1,21 +1,34 @@
 import numpy as np
 import matplotlib.pyplot as plt
 import sys
 
-if (not len(sys.argv) == 2):
-  print("Please give the data file as the only argument for this program")
+if (not len(sys.argv) == 3):
+  print("Please give the data file as the first argument and the separator as the second argument to this program")
   sys.exit()
 
 file_name = sys.argv[1]
-data = np.loadtxt(file_name, delimiter = " ")
+
+if sys.argv[2] == "comma":
+  separator = ","
+elif sys.argv[2] == "space":
+  separator = " "
+elif sys.argv[2] == "tab":
+  separator = "\t"
+elif sys.argv[2] == "pipe":
+  separator = "|"
+else:
+  print("not known separator! please choose one of {comma, space, tab, pipe}")
+  exit(0);
+
+data = np.loadtxt(file_name, delimiter = separator)
 
 plt.figure()
 plt.plot(data[:,0], data[:,1], '-bo')
 if (np.shape(data)[1] == 3):
-  plt.plot(data[:,0], data[:,1]/data[:,2]*100.0, '-r', linewidth=2)
+  plt.plot(data[:,0], data[:,1]/data[:,2]*100.0, '-r', linewidth=4)
   plt.legend(['Series','Analytical value'], loc = 4)
 plt.grid()
 plt.xlabel("i")
 plt.ylabel("value")
 plt.show()
 
diff --git a/homework2/src/dumper_series.h b/homework2/src/dumper_series.h
index a2bcefa..0e074a5 100644
--- a/homework2/src/dumper_series.h
+++ b/homework2/src/dumper_series.h
@@ -1,27 +1,33 @@
 
 #ifndef DUMPER_SERIES
 #define DUMPER_SERIES
 
 #include "Series.hh"
 #include <iostream>
 
 class DumperSeries{
   public:
     DumperSeries(Series & series):series(series)
     {
     }
     
     virtual void dump(std::ostream & os) = 0;
     
     virtual void setPrecision(unsigned int precision)
     {
       this->precision = precision; 
     }
 
   protected:
     Series & series;
     unsigned int precision = 8;
 
 };
 
+inline std::ostream & operator << (std::ostream & stream, DumperSeries & _this)
+{
+  _this.dump(stream);
+  return stream;
+}
+
 #endif
diff --git a/homework2/src/main.cc b/homework2/src/main.cc
index 157c960..1112646 100644
--- a/homework2/src/main.cc
+++ b/homework2/src/main.cc
@@ -1,88 +1,92 @@
 //main
 
 #include "ComputeArithmetic.hh"
 #include "ComputePi.hh"
 #include "print_series.h"
 #include "write_series.h"
 #include "arglist.hh"
 #include <iostream>
 #include <sstream>
 #include <fstream>
 #include <stdlib.h>
 
 using namespace std;
 
 int main(int argc, char ** argv){
 
 
     ArgList args(argc, argv, "Computation of numerical Series");
 
     const string which_series = args.getstr("-st", "--seriestype", "pi", " type of series, one of [arithmetic, pi]");
     const string which_dumper = args.getstr("-dt", "--dumpertype", "print", " type of output");
     const string separator = args.getstr("-sep", "--sep", "", "");
     const string fname = args.getstr("-o", "--outfile", "", "name of the output file");
     const int frequency = args.getint("-f", "--freq", 2, "...");
     const int maxiter = args.getint("-Nmax","--Nmax", 100, "...");
 
     if (which_dumper=="write" & ((separator=="")||(fname==""))){
         cerr<<"to write the output on a file, specify the file name (-o) and the separator (-sep) "<<endl;
     }
 
 
     //command line arguments: Type of series and N of terms.
 
     //stringstream sstr;
     //for (int i = 1 ; i < argc ; ++i){
     //    sstr << argv[i] << " ";
     //}
 
     //string which_series;
     //string which_dumper;
     //int frequency;
     //int maxiter;
     //sstr >> which_series;
     //sstr >> which_dumper;
     //sstr >> frequency;
     //sstr >> maxiter;
 
     Series * my_series = NULL;
     DumperSeries * my_dumper = NULL;
 
     if (which_series == "pi")
         my_series = new ComputePi();
     else if (which_series == "arithmetic")
         my_series = new ComputeArithmetic();
     else {
         cout<<"insert one of the two available options:"
               "\n\t arithmetic (to compute arithmetic series)"
               "\n\t pi (to compute Pi series)"<<endl;
         return EXIT_FAILURE;
     }
 
-    std::ostream * os = &std::cout;;
+    std::ostream * os;
+    std::string file_name = "data.txt";
+    std::ofstream file(file_name.c_str());
     if (which_dumper == "print"){
         my_dumper = new PrintSeries(*my_series, frequency, maxiter);
+        os = &std::cout;
+        //os = & file;
+        my_dumper->setPrecision(6);
     }else if (which_dumper == "write"){
         my_dumper = new WriteSeries(*my_series, frequency, maxiter, separator);
+        os = & file;
     }else {
         cout<<"insert one of the two available options:"
               "\n\t print (to print on screen)"
               "\n\t write (to write in file)"<<endl;
         return EXIT_FAILURE;
     }
 
-    ofstream file(fname.c_str());
-    os = & file;
-    my_dumper->setPrecision(12);
-    my_dumper->dump(*os);
-    
-    file.close();
+
+    //my_dumper->dump(*os);
+    *os << *my_dumper;
+
 
     //double tmpi = my_series->compute(N);
 
     //cout<<"Result for the "<<which_series<<" series with "<<N<<" terms is "<< tmp<<endl;
 
     delete my_series;
     delete my_dumper;
     return 0;
 }
diff --git a/homework2/src/print_series.cc b/homework2/src/print_series.cc
index ba85b64..319a3bb 100644
--- a/homework2/src/print_series.cc
+++ b/homework2/src/print_series.cc
@@ -1,23 +1,23 @@
 #include "print_series.h"
 
 PrintSeries::PrintSeries(Series & series, int frequency, int maxiter):
   DumperSeries(series){
   this->frequency = frequency;
   this->maxiter = maxiter;
 }
 
 void PrintSeries::dump(std::ostream & os){
   os.precision(precision);
   for(int i=frequency; i<maxiter; i += frequency){
     double value = series.compute(frequency);
     os<<"i == "<<i<<" , series == "<<value;
-    double analytic_value = 3.0;// series.getAnalyticPrediction();
+    double analytic_value = series.getAnalyticPrediction();
     if(analytic_value != analytic_value){
       os<<std::endl;
     }else{
       double convergence_percent = (value/analytic_value) * 100.0;
       os<<" , convergence percent == "<<convergence_percent<<std::endl;
     }
   }
 }