数据结构——链表（头结点循环链表）

头文件：

#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 

功能函数：

#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;
}

main函数：

#include <stdio.h>
#include "LinkList.h"

int main()
{
    // 创建链表
    Node* head = Create_List();
    if (head == NULL)
    {
        printf("创建链表失败\n");
        return -1;
    }


    int i;
    for (i = 0; i < 10; i++)
    {
        Insert_Head(head, i);
    }
#if 0       
    for (i = 0; i < 10; i++)
    {
        Insert_Head(head, i);
    }

    Insert_Pos(head, 5, 1000);
    Insert_Pos(head, 1, 2000);
    Insert_Pos(head, 22, 2000);
    Insert_Pos(head, 24, 2000);
    Insert_Pos(head, 26, 2000);
    Delete_Pos (head, 21);

    Reverse_List(head);
#endif
    Delete_Data(head, 0);

    int x;
    Find_Element(head, 7, &x);
    Get_Element(head, 8, &x);
    printf ("%d\n", x);

    printf ("%d\n", Get_Len(head));
    Display(head);
    Clean_List(head);
    printf ("清空后：\n");
    Display(head);

    return 0;
}