Dear rooters, I create a TFile with two subdirectories: TFile = histofile.root TDirectory subdirectories pythia, zjet If I open the file in the TBrowser I can perfectly well access the histograms but I need to to this in a macro. I attached the histofile.root my Macro: #include <TH2.h> #include <iostream> TH1F *h; int plot(){ TFile *f = new TFile("histofile.root"); pythia->cd(); char hname[20]; sprintf(hname,"h[%d]",0); h=(TH1F*)f->Get(hname); h->Draw(); } gives root [0] Processing plot.C... Error: illegal pointer to class object h 0x0 137 FILE:plot.C LINE:27 *** Interpreter error recovered *** second problem: ----------------------------------------------------------------------- if I do root histofile.root root [0] Attaching file histofile.root... root [1] pythia->cd() (Bool_t)1 root [2] gDirectory->pwd() histofile.root:/pythia root [3] gDirectory->cd() (Bool_t)1 root [4] zjet->cd() Error: Symbol zjet is not defined in current scope FILE:/tmp/fileihS306_cint LINE:1 Error: Failed to evaluate zjet->cd()Possible candidates are... filename line:size busy function type and name *** Interpreter error recovered *** But it is there. I can see it in the TBrowser. What do I do wrong? Thank you so much. Meta -- ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Thank you" means you don't have to, but I'm glad you did! ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Meta Binder FNAL, M.S. 357 LMU Muenchen Meta Binder Sektion Physik P.O. Box 500 Am Coulombwall 1 Batavia, IL 60510 85748 Garching ph: +49 89 289- 14149 ph: +1 630 840 3696 fax: +1 630 840 6650
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