头结点循环链表

头文件部分

#ifndef __LINKLIST_H__
#define __LINKLIST_H__


#define FALSE 0
#define TRUE  1


typedef int LinkData;
typedef struct _node
{
LinkData data;
struct _node * next;
}Node;


// 创建链表
Node * Create_List();


// 尾插
int Insert_Last(Node *h, LinkData data);


// 头插
int Insert_Head(Node *h, LinkData data);


// 在第 pos 个结点处插入数据
int Insert_Pos(Node *h, int pos, LinkData data);


//删除 第 pos 个结点
int Delete_Pos(Node* h, int pos);


// 逆序
int Reverse_List(Node *head);


// 删除指定数据
int Delete_Data(Node*, LinkData data);


// 查找元素:如果有, 返回元素的位置
int Find_Element(Node* h, LinkData data, int *x);


// 获取顺序表中的元素：通过位置获取
int Get_Element(Node* s, int pos, int *x);


int Get_Len(Node * head);


// 清空所有结点
int Clean_List(Node * head);


// 销毁链表
int Destroy(Node *);


void Display(Node *h);
#endif 

linklist.c部分

#include "LinkList.h"
#include <stdlib.h>
#include <stdio.h>
Node * Create_List()
{
Node *head = (Node*)malloc(sizeof(Node)/sizeof(char));
if (head == NULL)
return NULL;

head->next = head;   // 空表

return head;
}


int Insert_Head(Node *h, LinkData data)
{
if (h == NULL)
return FALSE;
Node *node = (Node*)malloc(sizeof(Node)/sizeof(char));
if (node == NULL)
{
return FALSE;
}

node->data = data;
node->next = h->next;

h->next = node;

return TRUE;
}


int Insert_Last(Node *h, LinkData data)
{
if (h == NULL)
return FALSE;

Node *node = (Node*)malloc(sizeof(Node)/sizeof(char));
if (node == NULL)
{
return FALSE;
}
node->data = data;
node->next = h;

Node* tmp = h;
while (tmp->next != h)
{
tmp = tmp->next;
}

tmp->next = node;

return TRUE;
}


int Insert_Pos(Node *h, int pos, LinkData data)
{
if (h == NULL || pos < 1)
return FALSE;

// 找要插入位置的前一个结点
Node *tmp = h;
int i;
for (i = 0; i < pos-1; i++)
{
if (tmp == h)
break;
tmp = tmp->next;
}

if (tmp == h)   // 越界
{
printf("插入位置越界\n");
return FALSE;
}

Node *node = (Node*)malloc(sizeof(Node)/sizeof(char));
if (node == NULL)
{
return FALSE;
}
node->data = data;
node->next = tmp->next;
tmp->next  = node;

return TRUE;
}


int Delete_Pos(Node* h, int pos)
{
if (h == NULL || pos < 1)
return FALSE;

// 找要插入位置的前一个结点
Node *tmp = h;
int i;
for (i = 0; i < pos-1; i++)
{
if (tmp->next == h)
break;
tmp = tmp->next;
}

if (tmp->next == h)   // 越界
{
printf("删除位置越界\n");
return FALSE;
}

Node *p = tmp->next;
tmp->next = p->next;
free(p);

return TRUE;
}


int Reverse_List(Node *h)
{
// h->next 空表
// h->next->next 只有一个结点
if (h == NULL || h->next == h || h->next->next == h)
return FALSE;

Node *pre = h->next;
Node *cur = h->next->next;
Node *tmp;

while (cur == h)
{
tmp = cur->next;
cur->next = pre;
pre = cur;
cur = tmp;
}

h->next->next = h;
h->next = pre;

return TRUE;
}


int Delete_Data(Node* h, LinkData data)
{
if (h == NULL)
return FALSE;

Node *tmp = h;
while (tmp->next != h)
{
if (tmp->next->data == data)
break;
tmp = tmp->next;
}

if (tmp->next == h)
return FALSE;

Node *p = tmp->next;
tmp->next = p->next;
free(p);

return TRUE;
}


int Find_Element(Node* h, LinkData data, int *x)
{
if (h == NULL)
return FALSE;

Node *tmp = h->next;
int k = 1;
while (tmp != h)
{
if (tmp->data == data)
{
*x = k;
return TRUE;
}
k++;
tmp = tmp->next;
}

return FALSE;
}


int Get_Element(Node* h, int pos, int *x)
{
if (h == NULL || pos < 1)
return FALSE;

int i;
Node *tmp = h;
for (i = 0; i < pos; i++)
{
if (tmp == h)
break;
tmp = tmp->next;
}

if (tmp == h)
return FALSE;
else
*x = tmp->data;

return TRUE;
}


int Get_Len(Node * h)
{
if (h == NULL)
return 0;

Node *tmp = h;
int count = 0;
while (tmp->next != h)
{
count++;
tmp = tmp->next;
}

return count;
}


int Clean_List(Node * h)
{
if (h == NULL)
return FALSE;

Node *tmp = h;
while (tmp->next != h)
{
Delete_Pos(h, 1);
}

return 0;
}




void Display(Node *h)
{
if (h == NULL)
return;

int count = 0;
Node *tmp = h->next;
while (tmp != h)
{
if (count++ % 4 == 0)
printf ("\n");
printf ("%8d", tmp->data);

tmp = tmp->next;
}
printf ("\n");
}


int Destroy(Node *h)
{
if (h == NULL)
return FALSE;
Clean_List(h);
free(h);

return TRUE;
}