#include <iostream>
using namespace std;


struct doubleNode
{
int data;
doubleNode *next;
doubleNode *prior;
};


typedef doubleNode* LinkList;


void init(LinkList *List);
bool insert(LinkList *List, int location, int data);
void show_position(LinkList List);
void show_reverse(LinkList List);
bool Delete(LinkList *List, int location);




int main()
{
LinkList List;
init(&List);
for (int i = 1; i <= 10; i++)
{
insert(&List, i, i * 10);
}
Delete( &List,11);
show_position(List);
show_reverse(List);
system("pause");
return 0;
}


void init(LinkList *List)
{
LinkList s = (LinkList)malloc(sizeof(doubleNode));
s->data = -1;
s->next = 0;
s->prior = 0;
*List = s;
}


bool insert(LinkList *List,int location,int data)
{
int j = 1;
LinkList p = *List;


if (location < 1)
{
cout << "erro" << endl;
return false;
}


while (j < location&&p != NULL)
{
j++;
p = p->next;
}


if (p == NULL)
{
cout << "insert erro" << endl;
return false;
}


LinkList s = (LinkList)malloc(sizeof(doubleNode));
s->data = data;
s->prior = p;
s->next = p->next;
if (p->next)//非迴圈雙向連結串列，在表尾插入節點時，不進行改操作。原因是空指標。
{
s->next->prior = s;
}
p->next = s;
return true;
}


//
void show_position(LinkList List)
{
List = List->next;
cout << "position direction display: ";
while (List)
{
cout << List->data << " ";
List = List->next;
}
cout << endl;
}


void show_reverse(LinkList List)
{
while (List->next)
{
List = List->next;
}
cout << "reverse direction display: ";
while (List->prior)
{
cout << List->data << " ";
List = List->prior;
}
cout << endl;
}


bool Delete(LinkList *List, int location)
{
int j = 1;
LinkList p = *List;


if (location < 1)
{
cout << "delete erro" << endl;
return false;
}


while (j < location&&p->next != NULL)
{
p = p->next;
j++;
}


if (p->next == NULL)
{
cout << "delete erro" << endl;
return false;
}


p = p->next;//待刪除指標
p->prior->next = p->next;


if (p->next)//如果不是刪除尾節點
{
p->next->prior = p->prior;
}
free(p);


return true;
}
 

插入操作：需要注意的是，如果是要在尾節點插入，不需要s->next->piror=s這一步，因為s->next為空。

刪除操作：需要注意的是，如果是刪除最後一個節點，不需要

p->next->prior = p->prior;

因為p->next是空指標