c++ - circular linked list assignment operator -

i need implement assignment operator = on circular linked list , here struct , code far. not sure how copy coefficient , power

struct term {                             // term on sparce polynomial      double coeff;                         // coefficient of each term      int power;                                    // degree of each term      term *prev;                     // pointer previous higher term     term *next;                          // pointer next lower term }; int size;                               // # terms in sparce polynomial term *head;               // pointer doubly-linked circular list of  polynomial& polynomial::operator=(const polynomial &rightpoly){   // check self assignment  if(&rightpoly !=this){      // clear      if(head !=null)          delete this;      if(rightpoly.head == null)          return *this;      // make new node head      term *ptr = new term;       head = ptr;      term *curright = rightpoly.head ->next;      term *curleft = ptr;       // traverse list, making new node , copying data      // until rightpoly empty      while (curright !=null) {          curleft ->next = new term;          curleft = curleft ->next;          curright = curright ->next;      }      curleft ->next = null;  }  return *this; }