cern root gSystem错误

Question

我尝试通过youtube视频教授CERN ROOT [视频标题是初学者的CERN ROOT教程 - 3.用结构和类编写一个树（例4-5）]，但它没有用。

  

错误：未知类型名称＆＃39; particle_CLASS＆＃39;

这是我的代码

void example5() {
   TTree t("t","a simple Tree with struct")
   gSystem->Load ("particle_CLASS_h.so");
   particle_CLASS* sParticle = new particle_CLASS();

   t.Branch ("particle_info", &sParticle);
   sParticle->Set_energy(11);
   sParticle->Set_position(1.1, 2.2, 3.3);
   t.Fill();

   sParticle->Set_energy(99);
   sParticle->Set_position(191., 291., 391.);
   t.Fill();

   TFile f("example5.root","recreate");
   t.Write();
   f.Close();
   }

和partivle_CLASS.h代码

class particle_CLASS: public TObject {
private:
    Float_t position[3]; 
    Float_t energy; 
public:
    particle_CLASS() { } // empty constructor
    //----Setter----
void Set_position(Float_t x, Float_t y, Float_t z) 
{
    position[0] = x; position[1] = y; position[2] = z;        
}


void Set_energy(Float_t e) { energy = e;}

//----Getter----
Float_t* Get_position() { return position; }
Float_t  Get_energy()   { return energy; }

ClassDef(particle_CLASS,1)  
/*
|   ClassDef is a C preprocessor macro 
|   that must be used if your class derives from TObject.
*/
};