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

void hrandom() {
   // example of a script computing the CPU time to fill an histogram
   // with 3 random number generators.
   
   const unsigned int nfills = 1000000;

   cout << "Llenando histogramas y midiendo eficiencias para " 
	<< nfills << " puntos" << endl;

   //Create timer to meassure performance
   TStopwatch timer;
   
   ////////////////////////////////////////////////////
   // First fill a histogram with a constant number

   //Create a histogram (see documentation)
   TH1F *h1 = new TH1F("h1","h1",100,0,1);

   //Start timer to meassure performance
   timer.Start();

   //Loop over histogram and fill it
   cout << "* Primer histograma..."  << endl;
   for (unsigned int i=0; i<nfills; i++) 
     h1->Fill(0.5);

   //Show times
   double fillTime = timer.CpuTime();
   cout << "  Tiempo: " << fillTime << " segundos" 
	<< endl;

   //Draw the histogram
   h1->Draw();

   /////////////////////////////////////////////////////
   //Second fill a histogram with random numbers (using TRandom)

   // Create a new canvas to avoid redrawing on the first one
   TCanvas *c2 = new TCanvas();

   // Create a new histogram (see documentation)
   TH1F *h2 = new TH1F("h2","h2",100,0,1);

   //Start timer to meassure performance
   timer.Start();

   //Create random generator (see documentation)
   TRandom r1;
   
   //Loop over histogram and fill it
   cout << "* Segundo histograma..."  << endl;
   for (unsigned int i=0; i<nfills; i++) 
     h2->Fill(r1.Rndm());
   cout << "  Tiempo: " << timer.CpuTime()-fillTime << " seconds\n" 
	<< endl;


   //Change histogram line color and draw it
   h2->SetLineColor(2);
   h2->Draw("");
}