void exemplo_TH1()
    {
      TRandom *r = new TRandom();
      TH1F *h1 = new TH1F("histograma","Exemplo histograma",50,0,10);
      for(int i = 0;i<2000;i++)
      {
        float x = r->Gaus(5,1);
        h1->Fill(x);
      }
      h1->Draw();
    }