#include <TMath.h>

void random2()
{
  TCanvas* c1 = new TCanvas ("c1","Random",100,10,700,500);

  const Double_t xMin = 0;
  const Double_t xMax = 1;//TMath::Pi();
  const Int_t nEv = 1000;
  
  TH1F* h1 = new TH1F ("h1","Random",100,xMin,xMax);
  
  TF1* f1 = new TF1 ("f1","gaus",xMin,xMax);
  f1->SetParameters(1,0.5,0.02);


  TF1* f2 = new TF1 ("f2","pol1",xMin,xMax);
  f2->SetParameters(1,10);

   h1->FillRandom("f1",nEv);
   h1->FillRandom("f2",10000);
   h1->Draw();
  
  // Fit di h1 con retta
  
  TF1* fAll = new TF1 ("fAll","gaus+x*[3]+[4]",xMin,xMax);
  fAll->SetParameters(1,1,0.01,1,100);
  h1->Fit("fAll");

  f2->SetParameters(fAll->GetParameter(4),fAll->GetParameter(3));
  f2->SetLineColor(2);
  f2->SetLineStyle(4);
  f2->Draw("same");

  TNtuple* ntuple = new TNtuple;

  TFile* file = new TFile ("pippo.root","RECREATE","Demo ROOT file with histograms");
  h1->Write();
  file->Close();
  
    }