{
  gROOT->Reset();


   c1 = new TCanvas("c1","A Simple Graph Example",200,10,700,500);
   const Int_t n = 20;
   Double_t x[n], y[n];
   for (Int_t i=0;i<n;i++) {
     x[i] = i*0.1;
     y[i] = 10*sin(x[i]+0.2);
     printf(" i %i %f %f \n",i,x[i],y[i]);
   }
   gr = new TGraph(n,x,y);
   gr->SetLineWidth(4);
   gr->SetMarkerStyle(21);
   gr->SetTitle("a simple graph");
   gr->GetXaxis()->SetTitle("X title");
   gr->GetYaxis()->SetTitle("Y title");
   gr->Draw("ACP");

   // TCanvas::Update() draws the frame, after which one can change it
   c1->Update();
   c1->GetFrame()->SetFillColor(21);
   c1->GetFrame()->SetBorderSize(12);
   c1->Modified();


  hpx    = new TH1F("hpx","This is the px distribution",100,-4,4);
  hpxpy  = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
  hprof  = new TProfile("hprof","Profile of pz versus px",100,-4,4,0,20);
  ntuple = new TNtuple("ntuple","Demo ntuple","px:py:pz:random:i");
// Fill histograms randomly
  gRandom->SetSeed();
  Float_t px, py, pz;
  const Int_t kUPDATE = 1000;
  for (Int_t i = 0; i < 25000; i++) {
     gRandom->Rannor(px,py);
     pz = px*px + py*py;
     Float_t random = gRandom->Rndm(1);
     hpx->Fill(px);
     hpxpy->Fill(px,py);
     hprof->Fill(px,pz);
     ntuple->Fill(px,py,pz,random,i);
     if (i && (i%kUPDATE) == 0) {
        if (i == kUPDATE) hpx->Draw();
        c1->Modified();
        c1->Update();
        if (gSystem->ProcessEvents())
           break;
     }
  }

   gDirectory->Append(gr);
   new TBrowser();
}