{
  gROOT->Reset();
  gStyle->SetOptFit(1);
  // Set the distribution function:
  TF1 func("distribution","[0]*(x^2)*exp(-(x^2)/[1])", -5., 5.);
  // Declare initial parameters:
  func.SetParameters(10., 4.);
  // Create the histogram:
  TH1D hist("hist","Plot of distribution", 100, -5, 5);
  // Fill random events according to func:
  hist.FillRandom("distribution",1000000);
  hist.Draw();

  // Fitting the histogram:
  func.SetLineColor(kRed); // Setting the fit line color to red
  func.SetParameters(1., 1.); // Resetting the parameters to something other than real values
  hist.Fit("distribution","M","",-5,5);
}