//----------- hrandom.C
#include "TStopwatch.h"
#include "TRandom2.h"
#include "TRandom3.h"
#include "TH1.h"
#include "TCanvas.h"
   
#include <iostream>

void hrandom2() {
   const unsigned int nfills = 100000;

   cout << "Histograma 2D para " << nfills << " puntos" << endl;

   ////////////////////////////////////////////////////
   // First fill a histogram with a constant number

   //Create a 2D histogram (see documentation)
   TH2F *h2d = new TH2F("h2D","Histogram in 2D (#sigma = 0)",40,-5,5,40,-5,5);


   //Create random generator (see documentation) 
   TRandom r1;
   
   //Loop over histogram and fill it
   for (unsigned int i=0; i<nfills; i++)
     h2d->Fill(r1.Gaus(), r1.Gaus());

   //Draw the histogram
   h2d->SetXTitle("Eje X");
   h2d->SetYTitle("Eje Y");
   h2d->SetZTitle("Eje Z");
   h2d->Draw("LEGO2");
}