#include <iostream>
#include "TH1F.h"
#include "TStyle.h"
#include "TCanvas.h"
#include "TLorentzVector.h"
#include "TClonesArray.h"
#include "TFile.h"
#include "TTree.h"
using namespace std;
void massclass()
{

TFile *hfile = new TFile("unweighted.root","read");

TTree *LHEF=(TTree*)hfile->Get("LHEF");
LHEF->SetMakeClass(true);

LHEF->SetBranchStatus("*",0);
LHEF->SetBranchStatus("Particle.M",1);
LHEF->SetBranchStatus("Event_size",1);
Long64_t nentries = LHEF->GetEntries();

Double_t *Particle_M[8];

LHEF->SetBranchAddress("Particle.M",Particle_M);
TH1F *invm = new TH1F("H_invmass","GeV",100,0,150);
Double_t k;
Int_t i=0;
for (i=0; i<10000;i++) 
{
LHEF->GetEntry(i);
for (Int_t j=0; j<8 ;j++)
{
k=*(Particle_M[j]);
cout<< Particle_M[j]<<endl;
invm->Fill(k);
}
cout<<i<<endl;
}
invm->Draw();

}