void print(){
  TCanvas* c = new TCanvas("c","c",0,0,700,500);

  TH1F* hframe = c->DrawFrame(0,0,1,1);

  // using a pointer the text will stay
  TLatex* tex1 = new TLatex( 0.25, 0.50, "text stays" );
  tex1->SetNDC();
  tex1->Draw();

  // the text will disappear if not using a pointer
  TLatex tex2( 0.50, 0.50, "text disappears" );
  tex2.SetNDC();
  tex2.Draw();

  gSystem->Sleep(1000);

  c->Modified();
  c->Update();

  gSystem->Sleep(1000);
}