c++ - Segmentation fault with my Move assignment opertaor overloading -

note: bug in program in question has been find, , rearrange content of question. if have similar problem, post recommend check not move assignment operator destructor.

first, can see image know data structure of classes below. enter image description here

.h

class list{ public:   // destructor   ~list();   // default constructor   list();   // move assignment operator   list& operator=(list&& src); private:   node* lead; ///boundary sentinel: dummy head     node* new_dummy_head(); 

};

.cc

// destroctors list::~list(){   node* cur = lead->next;   node* nex = cur->next;   while(cur->data!=null){     delete cur;     cur = nex;     nex = nex->next;   }   delete lead; }  // default constructors (just create dummy node) list::list(){   lead = new_dummy_head(); }  // move assignment operator overloading  list& list::operator=(list&& src){   // release resources *this owns , reset *this   // not point of question, hide    // pilfer src   lead = src.lead;    // reset source object   src.lead = null;   return *this; }  node* list::new_dummy_head(){   node* ptr = new node;   cerr << ptr->data << endl;   ptr->prev = ptr->next = ptr;   return ptr; } 

main.cc

int main() {   list beta;   beta = list();   return 0; } 

and get

segmentation fault 

in program, destructor of list assume there's dummy node pointed lead, can see in definition of move assignment operator

  // reset source object   src.lead = null;   return *this; 

it set lead of rvalue object null, segmentation fault when destroy move-from object