{

  //   Connect file generated in $ROOTSYS/test
  TFile f("toto.root");
  TLeaf *leaf_eln = physics->GetLeaf("el_n");
  TLeaf *leaf_elpt = physics->GetLeaf("el_pt");
  
  cout<<"el_n is "<<leaf_eln->GetTypeName()<<endl;
  cout<<"el_pt is "<<leaf_elpt->GetTypeName()<<endl;
  
  bool address=true;

  for(int i=0;i<10;i++)
    {
      leaf_eln->GetBranch()->GetEntry(i);
      int nbel = leaf_eln->GetValue();
      cout<<"Number of electrons "<<nbel<<endl;

      leaf_elpt->GetBranch()->GetEntry(i);
      if(!address)
	{
	  for(int j=0;j<nbel;j++)
	    {
	      cout<<"  whose pt is  "<<leaf_elpt->GetValue(j)<<endl;
	    }
	}
      else
	{
	  float *elpt_adr = leaf_elpt.GetValuePointer();
	  for(int j=0;j<nbel;j++)
	    {
	      cout<<"  whose pt is  "<<*(elpt_adr+j)<<endl;
	    }
	}


    }
}