{
TFile* f = new TFile("events.root","RECREATE");

TTree* t = new TTree("Events","Event Tree");
Int_t var1;
float var2;
float var3;

t->Branch("var1", &var1, "var1/I");
t->Branch("var2", &var2, "var2/F");
t->Branch("var3", &var3, "var3/F");
    
var1=5; var2=3.1; var3=10.;
t->Fill();
var1=1; var2=7; var3=4.5;
t->Fill();

    t->Print();
    t->Show(1);
    t->Write();
    f->Close();
}