{
gROOT -> Reset();
TFile f("radioprotection_t3.root");

TDirectory* dir = (TDirectory*)f.Get("radioprotection_ntuple");
TTree* ntuple = (TTree*)f.Get("t");
ntuple -> Print();  
// Assigned the TTree to the pointer ntuple

Double_t ep[40];
Int_t nevent = Int_t(ntuple->GetEntries());

Double_t edep;
Double_t xx;
ntuple->GetBranch("edep")->SetAddress(&edep); 
ntuple->GetBranch("count")->SetAddress(&xx);

Double_t x[40], y[40];
for (Int_t i=0;i<40;i++) {
x[i] = i;   
y[i] = 0;
}

for ( Int_t i=0; i<nevent; i++ ) {
     ntuple->GetEvent(i);
     //std::cout << "ID " << xx << ": " << edep << " MeV" << std::endl;
     y[(Int_t)xx] += edep;
     std::cout<<" The sum is: " << y[i] <<std::endl;
   }

}