#include <cstdlib>

void riempi3() {

  TH1F histo("pippo","Numeri casuali",100,0.,1.);

  int num= 1000;
  for (int i = 0; i<num;++i) {
    float rnd=1.*rand()/RAND_MAX;
    histo.Fill(rnd);
  }

  histo.DrawCopy();
  cout << histo.GetRMS() << endl;

}