Logo ROOT   6.21/01
Reference Guide
clonesA_Event.C File Reference

Detailed Description

Example to write & read a Tree built with a complex class inheritance tree.

It demonstrates usage of inheritance and TClonesArrays This is simplified / stripped extract of an event structure which was used within the Marabou project.

To run this example, do:

root > .x clonesA_Event.C
#ifndef CLONESA_EVENT_SECOND_RUN
void clonesA_Event() {
std::string s1(__FILE__);
TString dir = gSystem->UnixPathName(s1.substr(0, s1.find_last_of("\\/")).c_str());
gROOT->ProcessLine(TString(".L ")+dir+"/clonesA_Event.cxx+");
#define CLONESA_EVENT_SECOND_RUN yes
gROOT->ProcessLine("#include \"" __FILE__ "\"");
gROOT->ProcessLine("clonesA_Event(true)");
}
#else
void clonesA_Event_w()
{
// protect against old ROOT versions
if ( gROOT->GetVersionInt() < 30503 ) {
cout << "Works only with ROOT version >= 3.05/03" << endl;
return;
}
if ( gROOT->GetVersionDate() < 20030406 ) {
cout << "Works only with ROOT CVS version after 5. 4. 2003" << endl;
return;
}
//write a Tree
TFile *hfile = new TFile("clonesA_Event.root","RECREATE","Test TClonesArray");
TTree *tree = new TTree("clonesA_Event","An example of a ROOT tree");
TUsrSevtData1 *event1 = new TUsrSevtData1();
TUsrSevtData2 *event2 = new TUsrSevtData2();
tree->Branch("top1","TUsrSevtData1",&event1,8000,99);
tree->Branch("top2","TUsrSevtData2",&event2,8000,99);
for (Int_t ev = 0; ev < 10; ev++) {
cout << "event " << ev << endl;
event1->SetEvent(ev);
event2->SetEvent(ev);
tree->Fill();
if (ev <3) tree->Show(ev);
}
tree->Write();
tree->Print();
delete hfile;
}
void clonesA_Event_r()
{
//read the Tree
TFile * hfile = new TFile("clonesA_Event.root");
TTree *tree = (TTree*)hfile->Get("clonesA_Event");
TUsrSevtData1 * event1 = 0;
TUsrSevtData2 * event2 = 0;
tree->SetBranchAddress("top1",&event1);
tree->SetBranchAddress("top2",&event2);
for (Int_t ev = 0; ev < 8; ev++) {
tree->Show(ev);
cout << "Pileup event1: " << event1->GetPileup() << endl;
cout << "Pileup event2: " << event2->GetPileup() << endl;
event1->Clear();
event2->Clear();
// gObjectTable->Print(); // detect possible memory leaks
}
delete hfile;
}
void clonesA_Event(bool /*secondrun*/) {
// Embedding this load inside the first run of the script is not yet
// supported in v6
// gROOT->ProcessLine(".L clonesA_Event.cxx+"); // compile shared lib
clonesA_Event_w(); // write the tree
clonesA_Event_r(); // read back the tree
}
#endif
Author
The ROOT Team

Definition in file clonesA_Event.C.