void tclread() { // read file generated by tclwrite // loop on all entries. // histogram center of lines TFile *f = new TFile("tcl.root"); TTree *T = (TTree*)f->Get("T"); TH2F *h2 = new TH2F("h2","center of lines",40,0,1,40,0,1); TClonesArray *arr = new TClonesArray("TLine"); T->GetBranch("tcl")->SetAutoDelete(kFALSE); T->SetBranchAddress("tcl",&arr); Long64_t nentries = T->GetEntries(); for (Long64_t ev=0;ev<nentries;ev++) { arr->Clear(); T->GetEntry(ev); Int_t nlines = arr->GetEntriesFast(); for (Int_t i=0;i<nlines;i++) { TLine *line = (TLine*)arr->At(i); h2->Fill(0.5*(line->GetX1()+line->GetX2()), 0.5*(line->GetY1()+line->GetY2())); } } h2->Draw("lego"); }