#ifndef __CINT__ 
# include <TFile.h>
# include <TTree.h>
# include <TChain.h>
# include <TString.h>
# include <TVector3.h>
# include <iostream>
using namespace std;
#endif

void 
CreateTree(Int_t i, Int_t m=3) 
{
  TClonesArray* array = new TClonesArray("TVector3");
  TFile*        file  = TFile::Open(Form("%03d.root", i), "RECREATE");
  TTree*        tree  = new TTree("T", "T");
  tree->Branch("vector", &array);
  cout << "  Writing tree " << tree->GetName() << " to file " 
       << file->GetName() << endl;
  for (Int_t j = 0; j < m; j++) {
    cout << "    Entry # " << j << endl;
    array->Clear();
    for (Int_t k = 0; k < j+1; k++) {
      Double_t x = 100 * i + 10 * j + k + .1;
      Double_t y = 100 * i + 10 * j + k + .1;
      Double_t z = 100 * i + 10 * j + k + .1;
      new ((*array)[k]) TVector3(x, y, z);
    }
    tree->Fill();
  }
  file->Write();
  file->Close();
}


void 
CreateChain(Int_t n=3, Int_t m=3) 
{
  cout << "Creating " << n << " files" << endl;
  for (Int_t i = 0; i < n; i++) CreateTree(i, m);
}


void 
ReadArray(TClonesArray* array=0) 
{
  Int_t o = array->GetEntries();
  cout << "      Reading " << o << " vectors from array" << endl;
  for (Int_t k = 0; k < o; k++) {
    TVector3* v = static_cast<TVector3*>(array->At(k));
    // cout << "    (" << v->X() << "," << v->Y() 
    //      << "," << v->Z() << ")" << endl;
  }
}

void 
ReadTree(TTree* tree=0) 
{
  cout << "  Reading from the tree " << tree->GetName() << endl;
  TClonesArray* array = new TClonesArray("TVector3");
  TClonesArray* other = new TClonesArray("TVector3");
  tree->SetBranchAddress("vector", &array);
  TTree*        clone = tree->CloneTree();
  clone->SetBranchAddress("vector", &other);
  Int_t         entry = 0;
  Int_t         read;
  while ((read = tree->GetEntry(entry)) > 0) {
    cout << "    Entry # " << entry << " (" << read << " bytes)" << endl;
    ReadArray(array);
    if (entry > 0) {
      read = clone->GetEntry(entry-1);
      cout << "      Clone Entry # " << entry - 1 
	   << " (" << read << " bytes)\n  " << std::flush;
      ReadArray(other);
    }
    entry++;
  }
}

void 
ReadFile(const Char_t* name="000.root") 
{
  cout << "Reading from the a single tree from file " << name << endl;
  TFile* file  = TFile::Open(name, "READ");
  TTree* tree  = static_cast<TTree*>(file->Get("T"));
  ReadTree(tree);
  file->Close();
}

void 
ReadChain() 
{
  cout << "Reading from the a chain of trees from"  << endl;
  TChain*       tree  = new TChain("T");
  tree->Add("0*.root");
  TFile*        file  = TFile::Open("foo.root", "RECREATE");
  ReadTree(tree);
}

void
Mixed()  
{
  CreateChain();

  ReadFile();
  
  ReadChain();
}