TClonesArray Problem

ROOT
1

HI rooters,
I wrote a short and simple script ,the script is just a test,i want to know how to use TClonesArray,and the difference between TObjArray and TClonesArray. So this is my code:
[color=brown]{ TFile *f=new TFile(“particleinfo.root”,“recreate”);
TClonesArray *particleinfo = new TClonesArray();
//TObjArray *particleinfo =new TObjArray();
TParticle *particle1 = new TParticle();
particle1->SetMomentum(300,300,200,700);
TParticle *particle2 =new TParticle ();
particle2->SetMomentum(100,100,100,400);
TParticle *particle3 =new TParticle ();
particle3->SetMomentum(-90,-80,100,300);

particleinfo->Add(particle1);
particleinfo->Add(particle2);
particleinfo->Add(particle3);
particleinfo->Write();
f->Close();

}[/color]
When i use the TObjArray ,there is no problem;
But when use TClonesArray ,the warning infomation is:
[color=red]Warning in TClonesArray::AddLast: may not use this method
Warning in TClonesArray::AddLast: may not use this method
Warning in TClonesArray::AddLast: may not use this method[/color]

SO ,what’s the problem??? When and How to use TClonesArray is better ??
Tanks a lot!

2

Hi,

Please review the user’s guide for the correct usage of TClonesArray. TClonesArray are most useful in the case of object stored in a TTree. TClonesArray does not support call to Add. Instead use: TParticle *particle3 =new (particleinfo->At(3)) TParticle (); particle3->SetMomentum(-90,-80,100,300);

Cheers,
Philippe.

3

Dear Philippe,
That helps, I have solved my problem,thank you very much. :smiley: