#include "RooDataSet.h"
#include "RooRealVar.h"
#include "RooArgSet.h"

#include "TFile.h"
#include "TTree.h"
#include "TString.h"

using namespace RooFit;

int DataSet2TreeConv(TString RootFile, TString DataSetName, TString TTreeFileName)
{
  TFile *inFile       = new TFile(RootFile,"OPEN");
  RooDataSet *DataSet = (RooDataSet*)inFile->Get(DataSetName);
  RooRealVar *mass    = new RooRealVar("mass","mass",0,10);

  RooArgSet *argSet;
  double dataSetValue;

  int entries = DataSet->numEntries();

  TFile *outFile = new TFile(TTreeFileName,"RECREATE");
  TTree *myTree  = new TTree(DataSetName,"TTree created from RooDataSet");
  myTree->Branch(mass->GetName(),&dataSetValue);

  for(int iEntry = 0; iEntry<entries; iEntry++)
    {
      argSet       = (RooArgSet*)DataSet->get(iEntry);
      mass         = (RooRealVar*)argSet->find(mass->GetName());
      dataSetValue = mass->getVal();
      myTree->Fill();
    }

  myTree->Write();
  outFile->Close();

  return -1;
}