双链表的插入和删除操作_r5-1双链表插入操作

目录

1、插入操作

2、删除操作

1、插入操作

s->next = p->next;        //将结点s插入到结点p之后
p->next->prior = s;
s->prior = p;
p->next = s;

        头插法建立双链表 

//头插法建立双链表（有头结点） 
DLinkList List_HeadInsert(DLinkList &L) {
	L = (DLinkList)(malloc(sizeof(DNode)));
	DNode *s;
	L->next = NULL;
	L->prior = NULL;
	int data_insert;
	cin>>data_insert;
	while (data_insert != 9999) {
		s = (DNode*)(malloc(sizeof(DNode)));
		s->data = data_insert;
		if (L->next == NULL) {		//第一个结点为空 
			L->next = s;
			s->prior = L;
			s->next = NULL;
		}
		else {
			s->next = L->next;
			L->next->prior = s;
		    s->prior = L;
		    L->next = s;
		}
		cin>>data_insert;
	}
	return L;
} 

2、删除操作

p->next = q->next;        //删除结点p的后继节点q
q->next->prior = p;
free(q);

//删除操作的实现
DLinkList DListDelete(DLinkList &L,int i){
	DNode *p = GetDNode(L,i-1);		//得到被删结点的前驱节点 
	DNode *q = p->next;
	p->next = q->next;
	q->next->prior = p;
	free(q);
}