William,
I suggest the following simplifications in your code:
1- In your class TDriftSpectrum, implement a constructor:
TDriftSpectrun::TDriftSpectrum(const char*name, const char*title,
Int_t nbins, Float_t xlow, Float_t xup)
:TH1F(name,title,nbins,xlow,xup)
{
SetDirectory(0);
}
2- Do not derive TDriftSpectrumInfo from TDriftSpectrum but
from TNamed.
3- In your main program, simply do:
d1->Write();
By default, TH1 objects are automatically added to the list of objects
in memory (you see them with gDirectory->ls();
The statement SetDirectory(0) will remove the object from this list.
d1->Write() will write one single key.
In your old code below, the statement f->Write() writes all objects
in the list in memory associated to the file f.
Rene Brun
> //__________________________________________________
> CINT/ROOT C/C++ Interpreter version 5.13.45, Mar 17 1998
> Type ? for help. Commands must be C++ statements.
> Enclose multiple statements between { }.
> root [0] TFile *f = new TFile("f:/test;3.root","recreate");
> root [1] TDriftSpectrumInfo *d1 = new TDriftSpectrumInfo("d1");
> root [2] Int_t i;
> root [3] for (i=1; i<3; i++) d1->Add(i);
> root [4] d1->Build();
> root [5] f.ls()
> TFile** f:/test;3.root
> TFile* f:/test;3.root
> OBJ: TDriftSpectrumInfo d1 d1 : 0
> OBJ: TDriftSpectrum drift1 drift1 : 0
> OBJ: TDriftSpectrum drift2 drift2 : 0
> OBJ: TDriftSpectrum drift3 drift3 : 0root [6] d1->Write()
> root [7] f->Write()
> TFile Writing Name=f:/test;3.root Title=
> root [8] f.Close()
> root [9]
>
> CINT/ROOT C/C++ Interpreter version 5.13.45, Mar 17 1998
> Type ? for help. Commands must be C++ statements.
> Enclose multiple statements between { }.
> root [0] TFile *f = new TFile("f:/test;3.root");
> root [1] f.ls()
> TFile** f:/test;3.root
> TFile* f:/test;3.root
> KEY: TDriftSpectrumInfo d1;2 d1
> KEY: TDriftSpectrumInfo d1;1 d1
> KEY: TDriftSpectrum drift1;1 drift1
> KEY: TDriftSpectrum drift2;1 drift2
> KEY: TDriftSpectrum drift3;1 drift3
> root [2]
>
> //__________________________________________________
> class TDriftSpectrum : public TH1F
> {
> public:
> TDriftSpectrum();
> TDriftSpectrum(Text_t* title);
> virtual ~TDriftSpectrum();
>
> ClassDef(TDriftSpectrum,1)
> };
>
> //__________________________________________________
> class TDriftSpectrumInfo : public TDriftSpectrum
> {
> public:
> TDriftSpectrumInfo();
> TDriftSpectrumInfo(Text_t *tname);
> virtual ~TDriftSpectrumInfo();
>
> TDriftSpectrum * Add(Int_t index);
> TDriftSpectrum * Add(Text_t *title);
>
> TObjArray *drift;
>
> protected:
> ClassDef(TDriftSpectrumInfo,1)
> };
>
> TDriftSpectrumInfo::TDriftSpectrumInfo(Text_t *tname) :
> TDriftSpectrum(tname)
> {
> drift = new TObjArray(500);
> drift->Clear();
> size = 0;
> }
>
> TDriftSpectrum * TDriftSpectrumInfo::Add(Int_t index)
> {
> Char_t title[256];
> sprintf(title,"drift%i",index);
> return Add(title);
> }
>
> TDriftSpectrum * TDriftSpectrumInfo::Add(Text_t *title)
> {
> if ((*drift)[size]) delete (*drift)[size];
>
> (*drift)[size] = new TDriftSpectrum(title);
> return (TDriftSpectrum *) (*drift)[size++];
> }