void hsimple()
{
//*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*
//*-*
//*-*  This program creates :
//*-*    - a one dimensional histogram
//*-*    - a two dimensional histogram
//*-*    - a profile histogram
//*-*    - a memory-resident ntuple
//*-*
//*-*  These objects are filled with some random numbers and saved on a file.
//*-*
//*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*

  gROOT->Reset();

// Create a new ROOT binary machine independent file.
// Note that this file may contain any kind of ROOT objects, histograms,
// pictures, graphics objects, detector geometries, tracks, events, etc..
// This file is now becoming the current directory.

  TFile *hfile = gROOT->FindObject("hsimple.root"); if (hfile) hfile->Close();
  hfile = new TFile("hsimple.root","RECREATE","Demo ROOT file with histograms");

// Create some histograms, a profile histogram and an ntuple
  hgauss    = new TH1F("hgauss","Gauss Distribution",100,-4,4);
  hbwigner  = new TH1F("hbwigner","Breit Wigner Distribution",100,-4,4);
  hexp      = new TH1F("hexp","Exponential Distribution",100,0,50);
  hpoisson  = new TH1F("hpoisson","Poisson Distribution",100,0,10);
  hmass     = new TH1F("hmass","Mass of pi, K, p",120,0,1.2);
  hist0     = new TH1F("hist0","",100,0,50);
  hist1     = new TH1F("hist1","",100,0,50);
  hist2     = new TH1F("hist2","",100,0,50);
  hist3     = new TH1F("hist3","",100,0,40);
  hist4     = new TH1F("hist4","",50,1.75,2.0);

//  Set canvas/frame attributes (save old attributes)

  gBenchmark->Start("hsimple");

// Fill histograms randomly
  gRandom->SetSeed();
  Double_t mean, sigma, tau, value;
  Int_t amari;

  for ( Int_t i=0; i<25000; i++) {
    /* gauss */
    mean=0.0;  sigma=1.0;
    value = gRandom->Gaus(mean,sigma);
    hgauss->Fill(value);
    mean=0.0;  sigma=0.8;
    value = gRandom->BreitWigner(mean,sigma);
    hbwigner->Fill(value);
    tau = 12.3;
    value = gRandom->Exp(tau);
    hexp->Fill(value);
    mean = 4;
    value = gRandom->PoissonD(mean);
    hpoisson->Fill(value);
  }

  for ( Int_t i=0; i<25000; i++) {
    amari=i%10;
    switch (amari) {
    case 0:
    case 1:
    case 2:
    case 3:
    case 4:
      mean = 0.938; sigma = 0.05;
      break;
    case 5:
    case 6:
      mean = 0.495; sigma = 0.03;
      break;
    case 7:
    case 8:
    case 9:
      mean = 0.139; sigma = 0.05;
      break;
    }
    value = gRandom->Gaus(mean,sigma);
    hmass->Fill(value);
  }


  TF1 *func2 = new TF1("func2","gaus(0)+[3]",0,50);
  func2->SetParameters(300,25,3,100);
  hist0->FillRandom("func2",25000);

  for ( Int_t i=0; i<25000; i++) {
    /* gauss */
    mean=25.0;  sigma=5.0;
    value = gRandom->Gaus(mean,sigma);
    hist1->Fill(value);
    tau = 12.3;
    value = gRandom->Exp(tau);
    hist1->Fill(value);
  }

  for ( Int_t i=0; i<25000; i++) {
    /* gauss */
    mean=13.0;  sigma=4.0;
    value = gRandom->Gaus(mean,sigma);
    hist2->Fill(value);
    mean=25.0;  sigma=3.0;
    value = gRandom->Gaus(mean,sigma);
    hist2->Fill(value);

  }

  TF1 *func = new TF1("func","gaus(0)+[3]+[4]*x+[5]*x*x",0,50);
  func->SetParameters(300,10,2,0,40,-1);
  hist3->FillRandom("func",50000);

  for (Int_t i=0; i<17000; i++) {
    mean=1.86;  sigma=0.017;
    value = gRandom->BreitWigner(mean,sigma);
    hist4->Fill(value);
  }

  gBenchmark->Show("hsimple");

// Save all objects in this file
  hfile->Write();
  
// Note that the file is automatically close when application terminates
// or when the file destructor is called.
}