using namespace RooFit;

void Main(){
  RooRealVar En("Energy","Energy",-5,5);
  RooRealVar mean("mean","mean",0);
  RooRealVar sigma("sigma","sigma",1);
  RooGaussian gss("gss","gss",En,mean,sigma);
  RooRealVar yield("yield","yield",TMath::Sqrt(2*TMath::Pi()));

  RooPolynomial poly("poly","poly",En,RooArgList());
  RooRealVar bkgy("bkgy","bkgy",10);

  RooAddPdf model("model","model",RooArgList(gss,poly),RooArgList(yield,bkgy));

  model.plotOn(P,LineColor(kBlue),Normalization(100000,RooAbsReal::NumEvent));

  RooCurve *func = (RooCurve*)P->getObject(0);
  cout << func->Eval(0) << endl;
  
  P->Draw();
}