Programming

#include <string>
#include "TFile.h"
#include <iostream>
#include "TH1.h"
#include "TCanvas.h"
#include <fstream>

void func2()
{
  using std::cin;
  using std::cout;
  using std::endl;

// new data
//TFile *_file_0 = TFile::Open("m-00.root");
TFile *_file_0 = TFile::Open("m-00.root");

// old data
//TFile *_file_1 = TFile::Open("m-00.root");
TFile *_file_1 = TFile::Open("m-00.root");

 char var[20];
 string mystr = "pre_ti_data_";
 string myc = "MyC";

 ifstream myfile;
 myfile.open("vars.txt");
 if (myfile.is_open())
   {
     while (!myfile.eof())
       {
	 myfile >> var;
         string dutt = mystr+var+";1";
         string sun1 = mystr+var+".eps";
         string sun2 = mystr+var+".jpg";
	 cout << "What is dutt? " << dutt << endl;

	 //Pass bdt and nn
	 //
	 //if (dutt == "pre_ti_data_bdt" || dutt == "pre_ti_data_nn")
	 //  continue;  ????
         //

	 //TCanvas *MyC = new TCanvas(dutt.c_str(), "", 1);

	 TH1* h0  = (TH1*) _file_0->Get(dutt.c_str());
	 TH1* h1  = (TH1*) _file_1->Get(dutt.c_str());

	 TH1F* rat_d = (TH1F*) h0->Clone();
	 rat_d->Reset();
	 rat_d->Divide(h0, h1);
	 rat_d->SetMaximum(0.5);
	 rat_d->SetMinimum(0.0);
	 
	 //
	 //*****************************************
	 //this is for fitting the ratios histogram:
	 //*****************************************
	 cout << "Fitting: " << dutt << "ratio" << endl;
	 //rat_d->Fit("pol1");
	 rat_d->Fit("pol0");  //fitting with a constant function
	 gStyle->SetOptFit(111);
	 //
	 
         TCanvas *MyC = new TCanvas(myc.c_str(),"",1);
         MyC->Divide(2,1);
         MyC->cd(1);
         rat_d->Draw();

	 MyC->cd(2);
	 h0->SetLineColor(2);
	 Double_t n0 = h0->Integral();
	 cout << "Number of events in h0: " << n0 << endl;

	 //
	 //To make sure I have no zeros on the denominator
	 if (n0 == 0) {
	   cout << "     >>>>>>>>>>>>>>>>>      " << endl;
	   cout << "  I got a zero in the denominator" << endl;
	   cout << "     >>>>>>>>>>>>>>>>>      " << endl;
	   continue;
	 }
	 //continue after passing the zero:
	 //

	 h0->Scale(1/n0); //h0->Scale(1/h0->Integral())

	 h1->SetLineColor(4);
	 Double_t n1 = h1->Integral();
	 cout << "Number of events in h1: " << n1 << endl;
	 h1->Scale(1/n1);

	 h0->Draw();
	 h1->Draw("same");
         cout << "sun1 : " << sun1 << '\n';
         cout << "sun2 : " << sun2 << '\n';
	 MyC->Print(sun1.c_str());
	 MyC->Print(sun2.c_str());
continue;
       }
     myfile.close();
   }

if(strstr(dutt, "pre_ti_data_bdt") != NULL || strstr(dutt, "pre_ti_data_nn") != NULL)
  continue;