See comments in the code below
Rene Brun
void NtupleRead()
{
//open the Tree file and read the Tree headers
TFile f1 = ("enw.root","READ");
TTree *T1 = (TTree*)f1.Get("T1");
TTree *T2 = (TTree*)f1.Get("T2");
//open the output file. Becomes the current dir.
//Newly created histograms will be automatically added to it
TFile f("test.root","RECREATE");
cHist = new TCanvas("cHist","Canvas 1",100,100,800,800);
cHist->Divide(2,2);
cHist->cd(1); T1->Draw("fEvis>>hEvis");
cHist->cd(2); T1->Draw("fPt>>hPt");
cHist->cd(3); T2->Draw("fPl>>hPl");
cHist->cd(4); T2->Draw("fNchg>>hNchg");
f.Write();
}
On Sat, 5 Jan 2002, Dennis C. Arrogancia wrote:
>
>
> Dear ROOTERS,
>
>
> I have a little problem regarding reading ntuples. I have a code below,
> I have a file which contains 2 ntuples "T1" and "T2". Since i want to draw
> thw data in a desired range, i place it in histograms. The histograms
> below are already initialized. My problem is how to save the result in a
> file where i can view the histograms one by one. What should be added in
> the code below to save the result in a file? I tried creating a file but
> its empty. What's wrong with the code below?
>
>
> void NtupleRead()
> {
>
> f = new TFile("test.root","RECREATE");
>
> f1 = new TFile("enw.root","READ");
> f1.cd();
>
> cHist = new TCanvas("cHist","Canvas 1",100,100,800,800);
> cHist->Divide(2,2);
>
> cHist->cd(1); T1.Draw("fEvis>>hEvis");
> cHist->cd(2); T1.Draw("fPt>>hPt");
> cHist->cd(3); T2.Draw("fPl>>hPl");
> cHist->cd(4); T2.Draw("fNchg>>hNchg");
> cHist->Update();
>
> f.Write();
>
> }
>
>
>
>
> Dennis Arogancia
> MSU-IIT
>
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