#include <iostream>
#include <vector>

#include "TH1F.h"
#include "TF1.h"
#include "TFile.h"
#include "TMath.h"

using namespace std;
using namespace TMath;

Double_t MultipleGammas(Double_t* x, Double_t* par)
{
  return x[0];
}

double FitMultipleGammas(TH1F* spec, double GammaEnergy)
{
  TF1* fitfun;
  fitfun = new TF1("fitfun", MultipleGammas, spec->GetXaxis()->GetXmin(), spec->GetXaxis()->GetXmax(), 4);

  fitfun->SetRange(GammaEnergy - 10., GammaEnergy + 10.);
  
  spec->Fit("fitfun", "RBN");

  cout<<"NDF: "<<fitfun->GetNDF()<<endl;
}

int main()
{
  TH1F* hist = new TH1F("hist","hist",100,0,100);

  hist->FillRandom("gaus",1000000);

  FitMultipleGammas(hist, 20.);

  return 0;
}