Reading hist from a TTree

I have a root file named “filename.root” with the tree named “treename”. There is a histogram named “histname” in this tree. I am trying to read this histogram but nothing is showing up. Please let me know my error. Here’s my code.

void TFileRead()
        TFile *filename = new TFile("filename.root", "READ"); //READ
        TTree *treename = (TTree*)filename->Get("treename");

//      TH1F* histname = (TH1F*)treename->GetHistogram("histname");


Can you give more details ? Which error message do you get ? May be post the file filename.root here ?

Hi Couet, here are the all the files. Thank you.

filename.root (6.7 KB)
TFileCreate.C (469 Bytes)
TFileRead.C (306 Bytes)

histname is not in the tree. It seats in the root file. Simply do:

% root filename.root 
  | Welcome to ROOT 6.25/01               |
  | (c) 1995-2021, The ROOT Team; conception: R. Brun, F. Rademakers |
  | Built for macosx64 on Jul 05 2021, 04:58:33                      |
  | From heads/master@v6-25-01-1526-g96258cd49b                      |
  | With Apple clang version 12.0.5 (clang-1205.0.22.11)             |
  | Try '.help', '.demo', '.license', '.credits', '.quit'/'.q'       |

root [0] 
Attaching file filename.root as _file0...
(TFile *) 0x7fb08e33a170
root [1] _file0->ls()
TFile**		filename.root	
 TFile*		filename.root	
  KEY: TTree	treename;1	treetitle
  KEY: TH1F	histname;1	histtitle
root [2] histname->Draw()
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