#include "TVector3.h"
void tree_with_vector()
{

TVector3 vPosition[5];
 int number[5];

 for(int i=0; i<5; i++) {
   vPosition[i] = TVector3(i,i+1, i+2);
   number[i] = i;
   //cout<<vPosition[i][1]<<endl;
 }


 ///create the tree
  TFile f("test.root","recreate");
  TTree t("tree","tree with vector");

  //
  t.Branch("Num", number,"number[5]/I");
  t.Branch("vector",&vPosition,"vposition[5]");
  // t.Branch("vector",&vPosition,"vposition");

  //
  t.Fill();
  t.Write();
  
}