Copy Constructor List::List(const List &o) { if (o.head == NULL) head = NULL; else { head = new Node; head->number = o.head->number; for (Node *c1=head,*c2=o.head; c2;c1=c1->next,c2=c2->next) { c1->next = new Node; c1->next->number = c2->number; } c1->next = NULL; } }