mfc - CList's AddTail() assertion error -

i trying create double-dimensional list in mfc in order save , work int , cstring data. so, i've tried this:

#include "a.h" //a.cpp  a::a() { }  a::~a() { }  //**********************  #pragma once // a.h class a: public cobject { public:     a();     virtual ~a();      int id;     cstring label;  };  //**********************  #include "a.h" #pragma once  // b.h  class b : public cobject { public:     b();     virtual ~b();      int anotherid;     cstring anotherlabel;     clist<a*, a*&> * alist;     clist<cstring, cstring&> * testlist; };  //note: b.cpp pretty same a.cpp  //*********************  //c.cpp  void c::foo() {     b * b = new b;     * = new a;     a->id = 1;     a->label = l"something";     b->alist->addtail(a); //assertion error!     cstring aux = l"another thing";     b->testlist->addtail(aux); //assertion error! } 

here's problem: when try use addlist() method, receive error "access violation reading location". first thought problem related cobject derived classes, not sure if real problem. i've tried new , delete overloading, problem became worst. ideas?

both list elements declared pointers, you'll need either allocate them or declare them as

clist<a*, a*&> alist;              // without "*" clist<cstring, cstring&> testlist; // without "*"