// Integral (# counts with errors) of red, green and blue (dashed) in x = (11,13) region


using namespace RooFit;


void fitExample3()
{
	   // Declare observable x
   RooRealVar x("x", "x", 7, 15);
 
   // Create two Gaussian PDFs g1(x,mean1,sigma) anf g2(x,mean2,sigma) and their parameters
   RooRealVar mean1("mean1", "mean of gaussian1", 10);
   RooRealVar mean2("mean2", "mean of gaussian2", 11);
   RooRealVar sigma1("sigma1", "width of gaussians", 0.5);
   RooRealVar sigma2("sigma2", "width of gaussians", 1);
 
   RooGaussian sig1("sig1", "Signal component 1", x, mean1, sigma1);
   RooGaussian sig2("sig2", "Signal component 2", x, mean2, sigma2);

   RooRealVar nSig1("nSig1", "", 100, 0., 10000.);
   RooRealVar nSig2("nSig2", "", 100, 0., 10000.);

   RooAddPdf modelSig("modelSig", "modelSig", RooArgList(sig1, sig2), RooArgList(nSig1,nSig2));

   RooRealVar slope("slope","slope",0.1);
   RooExponential modelBkg("Exp", "Exp", x, slope);
   
   RooRealVar Nsig("Nsig","number of signal events",500,0.,100000) ;
   RooRealVar Nbkg("Nbkg","number of background events",500,0,100000) ;
 
   RooAddPdf  model2("model2","",RooArgList(modelSig,modelBkg), RooArgList(Nsig,Nbkg));

   RooDataSet *data = model2.generate(x, 100000);



   model2.fitTo(*data);

   // Plot data and PDF overlaid
   RooPlot *xframe = x.frame(Title("Example of composite pdf=(sig1+sig2)+bkg"));
   data->plotOn(xframe);
   model2.plotOn(xframe);
 
   // Overlay the background component of model with a dashed line
   model2.plotOn(xframe);
   model2.plotOn(xframe, Components(sig1), LineStyle(kDashed));
   model2.plotOn(xframe, Components(sig2), LineColor(kRed), LineStyle(kDashed));
   model2.plotOn(xframe, Components(modelBkg), LineColor(kGreen), LineStyle(kDashed));
 
   xframe->Draw();


}