#include <iostream>
using namespace std;


double func(double* x, double* par) {
  double y = par[0]*exp(-((x[0]-par[1])/par[2])*((x[0]-par[1])/par[2])) // gaus
    + par[3]; // flat
  return y;
}


void test4() {
  int a=10;
  cout << a << endl;

  TH1F pippo("pippo","il mio pippo", 100, 0, 10);

  // loop
  for (int i =0 ; i <10000 ; ++i)
  {
    // prendo un numero casual dist come gaussia media 5 e sigma 1
    pippo.Fill(gRandom->Gaus(5.3,0.97));
    // riempio l'isto con il numero casuale
  }

  for (int i =0 ; i <10000 ; ++i) {
    pippo.Fill(gRandom->Rndm()*10.); // flat [0,1)
  }

  // pippo.Fill(5.6);
  // pippo.Fill(2.6,0.6);

  TF1 f("f",func,0.,10.,4);
  f.SetParLimits(2,0,100); // sigma == par[2] (0,100)
  f.SetParameter(0,500.);
  f.SetParameter(1,5.);
  f.SetParameter(2,1.);

  //pippo.Fit("gaus");
  pippo.Fit("f");
  pippo.DrawCopy("e");

  gStyle->SetOptStat(111111);
  gStyle->SetOptFit(111111);

  int num = pippo.GetEntries();
  cout << "num entries " << num << endl;
  cout << "media " << pippo.GetMean() << endl;
}