// ----------------------------------------------------------------------------------- //
/*
  ROOT macro for reading text (ASCII) files and writing ROOT Ntuples.

  The program also shows how to print (Latex table) into a file!

  Author: Troels C. Petersen (NBI/CERN)
  Email:  Troels.Petersen@cern.ch
  Date:   19th of September 2011
*/
// ----------------------------------------------------------------------------------- //

#include <TFile.h>
#include <TNtuple.h>
#include <fstream>
#include <iostream>

using namespace std;


// ----------------------------------------------------------------------------------- //
void AsciiToNtuple() {
// ----------------------------------------------------------------------------------- //

  // Reading from:
  ifstream in("DataSet_ElectronPion_2GeV.txt");

  // Writing to:
  TNtuple* ntuple = new TNtuple("ntuple", "Ntuple from Ascii",
				"Cher:nTRT:nHT:ECal0:ECal1:ECal2:ECal3:EHad0:EHad1:EHad2:Mu");
  FILE* textfile = fopen("LatexTable.tex", "w");
  fprintf(textfile, " Event &  Cher   &  fTRT  &   Ecalo0 \\\\ \n");
  fprintf(textfile, " \\hline \\\\ \n");

  int NeventsMax = 33000;  // Maximum number of events is 33120 (2 GeV) and 120800 (9 GeV).
  int Nevents = 0;
  double x[11];

  if (in.is_open()) {
    while ((!in.eof()) && (Nevents < NeventsMax)) {
      in >> x[0] >> x[1] >> x[2] >> x[3] >> x[4]
	 >> x[5] >> x[6] >> x[7] >> x[8] >> x[9] >> x[10];
      ntuple->Fill(x[0], x[1], x[2], x[3], x[4], x[5], x[6], x[7], x[8], x[9], x[10]);

      Nevents++;
      if (Nevents%1000 == 0) printf("  Read %6d events. \n", Nevents);

      if (Nevents < 10)
	fprintf(textfile, "  %3d &   %6.1f &  %5.3f &   %6.3f \\\\ \n",
		Nevents, x[0], x[2]/x[1], x[3]);
    }
  }
  in.close();

  fprintf(textfile, " \\hline \\\\ \n");
  fclose(textfile);

  printf("  Number of entries in total: %6d \n", Nevents);


//---------------------------------------------------------------------------------- 
// Write histograms to file:
//---------------------------------------------------------------------------------- 
  TFile *file = new TFile("DataSet_ElectronPion_2GeV.root","RECREATE","Histograms");

  ntuple->Write();
  
  file->Write();
  file->Close();
}



// ----------------------------------------------------------------------------------- //
/*

The Ntuple can be easily and quickly analysed by simple commands. An example can be
found below.


Examples of commands:
---------------------
[top:AsciiToNtuple] > root -l DataSet_ElectronPion_2GeV.root 
root [0] 
Attaching file DataSet_ElectronPion_2GeV.root as _file0...
root [1] TBrowser a
root [2] ntuple->Draw("Cher")
<TCanvas::MakeDefCanvas>: created default TCanvas with name c1
root [3] ntuple->Draw("Cher","nHT/nTRT > 0.20")
(Long64_t)8212
root [4] ntuple->Draw("Cher","nHT/nTRT < 0.05")
(Long64_t)4111
root [5] ntuple->Draw("Cher","nHT/nTRT < 0.05 && EHad0+EHad1+EHad2 > 0.2")
(Long64_t)780
root [6] ntuple->Draw("Cher","EHad0+EHad1+EHad2 > 0.2")                   
(Long64_t)1493
...
root [12] ntuple->Draw("ECal1","EHad0+EHad1+EHad2 > 0.2")                
(Long64_t)1493
root [13] ntuple->Draw("ECal1","Cher > 700 && nHT/nTRT > 0.25", "same")

*/
// ----------------------------------------------------------------------------------- //