Hi Yiqun,
This should work.
Which version of ROOT are you using?
Please read: http://root.cern.ch/root/roottalk/RoottalkRules.html
Rene Brun
On Tue, 17 Dec 2002, Yiqun Wang wrote:
> ROOTers:
>
> I am writing a program that reads TTree in a root file, does something,
> and then writes to another root file. I want to write histograms in
> seperate directories of the output file. Below is an example:
>
>
> void dirCd(void){
>
> TBrowser *b = new TBrowser();
>
> TH1F *h0 = new TH1F("h0", "h0", 100, -10, 10);
> h0->FillRandom("gaus",1000);
>
> TFile *f1 = new TFile("xxx.root");
>
> TFile *f2;
>
> f2 = new TFile("cdDir.root", "Recreate");
>
> TDirectory *d1 = f2->mkdir("d1");
> TDirectory *d2 = f2->mkdir("d2");
>
> d1->cd();
>
> TH1F *h1 = new TH1F("h1", "h1", 100, -10, 10);
>
> d2->cd();
>
> TH1F *h2 = new TH1F("h2", "h2", 100, -10, 10);
>
> h1->FillRandom("gaus",1000);
> h2->FillRandom("gaus",1000);
>
>
> f2->Write();
> f2->Close();
>
> f1->Close();
>
> f2 = new TFile("cdDir.root");
>
> }
>
>
> This macro fails at the two places when TDirectory::cd() is called. If you
> comment out both "d1->cd();" and "d2->cd();", the code will run (but "h1"
> and "h2" are created in "/" of file "f2".
>
> What is the problem? Or any suggestion to accomplish my goal in another way?
>
> Thanks!
>
> Yiqun Wang
>
>
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