#include "TFile.h"
#include "TROOT.h"
#include "TH1.h"
#include "TF1.h"
#include "TSpectrum.h"
#include "TCanvas.h"
#include "TMath.h"

void Ajay() 
{
 
   TFile *f = TFile::Open("eff_6.root", "READ"); //Open a root file
   if ((!f) || f->IsZombie()) {
      std::cout << "Failed to open eff_6.root!" << std::endl;
      return;
   }
 
   TH1F *h2 = (TH1F*)f->Get("h")->Clone();
 
   TSpectrum *s = new TSpectrum(); // Define “s”

   TH1 *hb = s->Background(h2,20,"Compton"); // Generate background
   h2->Add(hb,-1); // Subtract background
   h2->SetLineColor(kBlack); // Set different line color

   h2->Draw(); // Draw background

   Int_t nfound = s->Search(h2,2,"",0.15);
   printf("Found %d candidate peaks to fit\n",nfound);
 
   f->Get("h")->Draw("same");
   hb->Draw("same"); // Draw background over it

   Double_t *xpeaks = s->GetPositionX();
   Double_t *epeaks = new Double_t [8]{121.78, 244.69, 344.27, 778.90, 964.13, 1085.869, 1112.11, 1408.01};
   std::sort(xpeaks, xpeaks + 8);

   TGraph *g = new TGraph(nfound,&(xpeaks[0]),&(epeaks[0]));
   TF1 *f1 = new TF1("f1","pol2",1,3);
   f1->SetParameters(3, 0.3, 3);
   g->SetMarkerStyle(3);
   g->SetTitle("Energy(kev) Vs Channel;Channel;Energy");
   g->Fit("f1","Q");
   g->Draw("AP");
   gStyle->SetOptFit(1111);
}