doc/v624/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:406

TCanvas
The Canvas class.
Definition TCanvas.h:23

TClass
TClass instances represent classes, structs and namespaces in the ROOT type system.
Definition TClass.h:80

TClass::InheritsFrom
Bool_t InheritsFrom(const char *cl) const
Return kTRUE if this class inherits from a class with name "classname".
Definition TClass.cxx:4851

TClass::GetClass
static TClass * GetClass(const char *name, Bool_t load=kTRUE, Bool_t silent=kFALSE)
Static method returning pointer to TClass of the specified class name.
Definition TClass.cxx:2957

TFile
A ROOT file is a suite of consecutive data records (TKey instances) with a well defined format.
Definition TFile.h:54

TFile::Open
static TFile * Open(const char *name, Option_t *option="", const char *ftitle="", Int_t compress=ROOT::RCompressionSetting::EDefaults::kUseCompiledDefault, Int_t netopt=0)
Create / open a file.
Definition TFile.cxx:3997

TH1
TH1 is the base class of all histogram classes in ROOT.
Definition TH1.h:58

TIter
Definition TCollection.h:233

TKey
Book space in a file, create I/O buffers, to fill them, (un)compress them.
Definition TKey.h:28

TKey::GetClassName
virtual const char * GetClassName() const
Definition TKey.h:76

TKey::ReadObj
virtual TObject * ReadObj()
To read a TObject* from the file.
Definition TKey.cxx:750

TObject::Draw
virtual void Draw(Option_t *option="")
Default Draw method for all objects.
Definition TObject.cxx:197

TPad::Print
void Print(const char *filename="") const override
Save Pad contents in a file in one of various formats.
Definition TPad.cxx:4692

c1
return c1
Definition legend1.C:41

f1
TF1 * f1
Definition legend1.C:11