#include "TFile.h"
#include "TTree.h"

void histogram_qinv()
{
        //gStyle->SetOptStat(0);
      
        TFile *f2 = TFile::Open("toymodel_fluctuation_data.root");
        TH1F *Qinv_data = (TH1F*)gDirectory->Get("qinv_data");
        TH1F *Delta_pt_data = (TH1F*)gDirectory->Get("Del_pT_data");
        
        TFile *f1 = TFile::Open("toymodel_fluctuation_mixed.root");
        TH1F *Qinv_mixed = (TH1F*)gDirectory->Get("qinv_mixed");
        TH1F *Delta_pt_mixed = (TH1F*)gDirectory->Get("Del_pT_mixed");

        TH1F *ratio_qinv = (TH1F*)Qinv_data->Clone("ratio_qinv");
        TH1F *ratio_Del_pT = (TH1F*)Delta_pt_data->Clone("ratio_Del_pT");
       
        //Divide by another histohram
        ratio_qinv->Divide(Qinv_mixed);
        ratio_Del_pT->Divide(Delta_pt_mixed);
        ratio_qinv->GetYaxis()->SetTitle("data/mixed");
        ratio_Del_pT->GetYaxis()->SetTitle("data/mixed");
        
        //Histograms write into a root file
        TFile *f = new TFile("toymodel_qinv.root","RECREATE"); //create a root file 
        ratio_qinv->Write();
        ratio_Del_pT->Write();
        f->Write();  
        f->Close();
}