C++ - Basic garbage collector using reference counting -

ok, i'm trying implement garbage collector in c++ (a basic one) using concept of reference counting, , works there don't understand.
have 2 classes:

class called gc, incrementing , decrementing reference counter

class named tobject plays role of smart pointer(i overloaded * , -> operators, , = operator)

here code below: gc.cpp

#include <iostream>  using namespace std;  class gc { public:     gc(){         this->refcount = 0;//initialisation du compteur à 0     }      void incrementref(){         this->refcount++;//incrémentation du compteur de references     }      int decrementref(){         return this->refcount--;//décrementation du compteur de references     }      int getcounter(){//getter du compteur de references         return refcount;     }     ~gc(){}  private:     int refcount; //compteur de references }; 

tobject.cpp:

#include <iostream> #include "gc.cpp"  using namespace std;  template <class t> class tobject {  t *p; gc *gc;  public:     tobject(t *p){         cout<<"refobject"<<endl;         this->p = p;         gc = new gc();         this->gc->incrementref();     }      virtual ~tobject(){//destructeur         cout<<"delete tobject"<<endl;         if(this->gc->decrementref() == 0){             delete p;             delete gc;         }     }      t* operator->(){//surcharge de l'opérateur d'indirection         return p;     }      t& operator*() const {//surchage de l'opérateur         return *p;     }      tobject<t>& operator=(const tobject<t> &t){         if(this->gc->decrementref() == 0){             delete p;             delete gc;         }         this->p = t.p;         this->gc = t.gc;         this->gc->incrementref();         return *this;     }      gc getgc(){         return *gc;     } }; 

and here how tested in main:

tobject<int> t(new int(2)); cout<<"t1 counter: "<<t.getgc().getcounter()<<endl;//displays 1 tobject<int> t2(null); cout<<"t2 counter: "<<t2.getgc().getcounter()<<endl;//displays 1 t2 = t; cout<<"t1 counter: "<<t.getgc().getcounter()<<endl;//displays 2, why? cout<<"t2 counter: "<<t2.getgc().getcounter()<<endl;//displays 2 

i don't it, copied t in t2 , did not update t1! why reference counter updated too?

it's because, both t , t2 sharing same gc instance. @ overloaded = operator method :-

tobject<t>& operator=(const tobject<t> &t) {    if(this->gc->decrementref() == 0)    {         delete p;         delete gc;    }    this->p = t.p;    this->gc = t.gc;  // using same gc. instead, must using                      //  this->gc = new gc();     this->gc->incrementref();    return *this; }