#include <iostream>
#include <vector>

#include "TFile.h"
#include "TTree.h"

using namespace std;



int main(){
  
  TFile fDB("./testW.root","read", "demo");

  TTree* t= (TTree*)fDB.Get("t");
  
  vector<float> a;
  vector<float> b;
  
  t->SetBranchAddress("a", &a);  
  t->SetBranchAddress("b", &b);  
  
  for (int i=0; i<2; i++){
    t->GetEntry(i);
    //cout<<a[i]<<"  "<<b[i]<<endl;
    cout<<a.at(i)<<"  "<<b.at(i)<<endl;
  }
  
  fDB.Close();
  
  return 0;
  
}