doc/v618/loopdir_8C.html

void loopdir() {

   TFile *f1 = TFile::Open("hsimple.root");

   TIter keyList(f1->GetListOfKeys());

   TKey *key;

   TCanvas c1;

   c1.Print("hsimple.ps[");

   while ((key = (TKey*)keyList())) {

      TClass *cl = gROOT->GetClass(key->GetClassName());

      if (!cl->InheritsFrom("TH1")) continue;

      TH1 *h = (TH1*)key->ReadObj();

      h->Draw();

      c1.Print("hsimple.ps");

   }

   c1.Print("hsimple.ps]");

}


h
#define h(i)
Definition: RSha256.hxx:106

gROOT
#define gROOT
Definition: TROOT.h:414

TCanvas
The Canvas class.
Definition: TCanvas.h:31

TClass
TClass instances represent classes, structs and namespaces in the ROOT type system.
Definition: TClass.h:75

TClass::InheritsFrom
Bool_t InheritsFrom(const char *cl) const
Return kTRUE if this class inherits from a class with name "classname".
Definition: TClass.cxx:4737

TFile
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition: TFile.h:48

TFile::Open
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseGeneralPurpose, Int_t netopt=0)
Create / open a file.
Definition: TFile.cxx:3980

TH1
The TH1 histogram class.
Definition: TH1.h:56

TIter
Definition: TCollection.h:233

TKey
Book space in a file, create I/O buffers, to fill them, (un)compress them.
Definition: TKey.h:24

TKey::GetClassName
virtual const char * GetClassName() const
Definition: TKey.h:71

TKey::ReadObj
virtual TObject * ReadObj()
To read a TObject* from the file.
Definition: TKey.cxx:722

c1
return c1
Definition: legend1.C:41

f1
TF1 * f1
Definition: legend1.C:11