#include "TFile.h"
#include <iostream>
#include "TCanvas.h"
#include "TPad.h"
#include "TH1F.h"
#include "TH1D.h"
#include "TCanvas.h"
#include <TSystem.h>
#include <iostream>
#include <stdlib.h>
#include <iomanip>
using namespace std;

   void fit(){
   TFile *file = new TFile("fit.root", "READ");
   file->ls();

   TH1F* hist = (TH1F*)file->Get("Deltapt;1");

   TCanvas* c = new TCanvas("c", "delta_pt", 800, 600);
   c->SetLogy();

   hist->Sumw2();
   hist->Scale(1./hist->GetEntries(),"Width");
   hist->SetMaximum(100);
   hist->SetMinimum(1e-5);

   hist->Fit("gaus","","",-10,10);

   hist->Draw();

  gStyle->SetOptFit(1111);

}