Hi Jim,
Seems to be a typical C++ scoping problem. You should create a global
variable
for outfile and your histogram pointers, or better declare them as class
variables of your TSelector.
I would advice to create your histograms in the Begin Function because the
Fill function is called for each accepted entry.
Rene Brun
On Wed, 19 Sep 2001, Junjie Zhu wrote:
>
> Dear Rooters:
>
> I have one problem about how to fill a file, I use MakeSelector to
> generate two files: for example my.C and my.h, now I want to analyze some
> events, and fill some histograms, then store all histograms to one root
> file. The following is my code:
>
> #include "my.h"
> #include "TH2.h"
> #include "TStyle.h"
> #include "TCanvas.h"
>
>
> void my::Begin(TTree *tree)
> {
> //create a root file to put some histograms
> TFile *outfile = new TFile("histogram.root", "recreate");
>
> Init(tree);
> TString option = GetOption();
>
> }
>
> Bool_t my::ProcessCut(Int_t entry)
> {
> // Selection function
> // entry is the entry number in the current Tree
> // Read only the necessary branches to select entries.
> // return as soon as a bad entry is detected.
> // to read complete event, call fChain->GetTree()->GetEntry(entry)
>
> return kTRUE;
> }
>
> void my::ProcessFill(Int_t entry)
> {
> // function called for selected entries only
> // entry is the entry number in the current Tree
> // read branches not processed in ProcessCut and fill histograms
> // to read complete event, call fChain->GetTree()->GetEntry(entry)
>
>
> my code here, it creates many histograms
>
> }
>
> void my::Terminate()
> {
>
> //write all histograms into the root file
> outfile -> Write();
> outfile -> Close();
>
> }
>
>
> Error message is:
> No symbol outfile -> Write()
>
> what is the problem? I think maybe I put TFile *outfile=new TFile() in the
> wrong place, where should I put it? can anyone help me?
>
> Jim
>
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