[ROOT] how to look histos in a loop

From: ginn gin (ginng2001@yahoo.com)
Date: Thu Aug 28 2003 - 05:58:14 MEST 

Hi,
    I need to open a root file and look for histograms
and get the mean value of each histogram. One of the
cut is each time changing. I need to put this as i and
 initialize i in a for loop. Then i is the one of the
value in ntuple->Draw(.....). When I gave ctub == 6480
without for loop it works. With the for loop i need to
 give values for i= 6480,6481 etc. If I run following
it complains about i. How can I get this fixed. Any
hint or help is appreciated.

Thank you, 
gin
=========Here is the program and what is wrong ===

{
    Double_t ave;
    Int_t i;
     
     TFile f("mpeak.root");
     TH1F *h2= new TH1F("h2","",50,0.,1000);

     for( i=6480; i<6500; i++){
     ntuple->Draw("bpul>>h2","btub==55611&&ctub==i");
     ave = h2->GetMean();
     cout<<" average : "<<ave<<endl;
      }
}

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