已知一个带有头结点的双向循环L,结点结构为pre data next,其中pre和next分别指向其直接前驱和直接后继结点的指针。现要删除指针p所指向的结点,正确的语句序列是()
A.
p->next->pre=p->pre; p->pre->next=p->pre; free(p)
B.
p->next->pre=p->next; p->pre->next=p->next; free(p)
C.
p->next->pre=p->next; p->pre->next=p->pre; free(p)
D.
p->next->pre=p->pre; p->pre->next=p->next; free(p)