A.class a{int x=0;int y=1;} B.class b{int x=0;int y=1;}; C.class c{intx;int y;} D.class d{intx;int y;};
A.p=head->next;head->next=head->next->next;delete p; B.head->next=head->next->next;p=head->next;delete p; C.p=head;head=head->next;delete p; D.head=head->next;p=head;delete p;
A.q=p;delete p; B.p=q;delete q; C.q->next=p->next;delete p; D.p->next=q->next;delete q;