void drawAllBranches() {

  TCanvas *c1 = new TCanvas("c1"); 

  TFile *f = new TFile("tp_01b1s3r12Boff_22395-22397.root"); 
  TTree *t = (TTree*)f->Get("h202"); 

  cout << t->GetEntries() << endl;

  // -- Get list of branches for the tree
  TObjArray *o = t->GetListOfBranches(); 
  int m = o->GetEntries(); 
  cout << "Number of branches: " << m << endl;
  
  // -- Loop over all, and draw their variables into TCanvas c1
  int cnt(0); 
  for (int i = 0; i < m; ++i) {
    cnt = t->Draw(((TBranch*)(*o)[i])->GetName());
    c1.Update(); 
  }

}