数据结构之C语言实现双向链表

C语言实现双向链表

双向链表主要实现以下功能：

• 双向链表创建
• 节点头插
• 节点尾插
• 指定位置插入节点
• 节点删除
• 链表排序
• 链表求长

/****************************************************************************************************** 
 *   function：自定义一个双向链表，并完成一些双向链表的操作：创建链表、数据插入、数据删除、链表排序 
 *   author：yahai.zhang 
 *   time: 2018.7.15
 *   File Name：DList.c
 ******************************************************************************************************/ 

#include <stdio.h>

 /* 定义数据结构 */
struct DouLinkNode {
    int data ;               //链表中存放的数据，可以自定义数据结构 
    struct DouLinkNode *pre ,*next;
};

/* 双向链表创建 */ 
struct DouLinkNode *create(int n)
{   
    int x;
    struct DouLinkNode *head = (struct DouLinkNode *)malloc(sizeof(struct DouLinkNode));
    struct DouLinkNode *p,*s;
    p = head;
    p->pre = NULL;
    while(n) {
        s = (struct DouLinkNode*)malloc(sizeof(struct DouLinkNode));
        printf("input x:");
        scanf("%d",&x);
        s->data = x;
        p->next = s;
        s->pre = p;
        p = s;
        n--;
    }
    s->next = NULL;
    return head;
}

 /* 双向链表打印 */
void display(struct DouLinkNode *head)
{
    struct DouLinkNode *p = head->next;
    while(p->next) {
        printf("%d <---> ",p->data);
        p = p->next;
    }
    printf("%d \n ",p->data);
}

/* 链表头插节点 */
void insertListHead(struct DouLinkNode *pList, int data)
{
    struct DouLinkNode *pNode = (struct DouLinkNode *)malloc(sizeof(struct DouLinkNode));
    pNode->data = data;
    pNode->next = pList->next;
    pNode->pre = pList;
    if (NULL != pNode->next) {
        pNode->next->pre = pNode;
    }
    pList->next = pNode;
}

/* 链表尾插节点 */ 
void insertListTail(struct DouLinkNode *pList, int data)
{
    struct DouLinkNode *pNode = (struct DouLinkNode *)malloc(sizeof(struct DouLinkNode));
    pNode->data = data;
    struct DouLinkNode *pCur = pList; 
    while(NULL != pCur->next) {
        pCur = pCur->next;
    }
    pCur->next = pNode;
    pNode->pre = pCur;
    pNode->next = NULL;
}

/* 在链表的指定位置插入节点: index = 0 ---> 头插； index = length ---> 尾插 */
int insertList(struct DouLinkNode *pList, int data, int index)
{
    struct DouLinkNode *pCur = pList; 
    int len =  get_List_Length(pCur);
    if(index > len) {
        return -1;
    } else if (index == 0) {
        insertListHead(pList, data);
        return 0;
    } else if(index == len) {
        insertListTail(pList, data);
        return 0;
    }

    struct DouLinkNode *pNode = (struct DouLinkNode *)malloc(sizeof(struct DouLinkNode));
    pNode->data = data;
    pCur = pList;
    int i = 0;
    while( index--) {
        pCur = pCur->next;
    }
    pNode->next = pCur->next;
    pCur->next = pNode;
    pNode->pre = pCur;
    pNode->next->pre = pNode;   
}

/* 删除链表中的指定值 */
int deleteListNode(struct DouLinkNode *pList, int key)
{
    struct DouLinkNode *pPre = pList;
    struct DouLinkNode *pCur = pList->next;
    int count = 0; //记录删除节点个数 
    while(NULL!=pCur) {
        if(pCur->data == key) {
            if(NULL != pCur->next) {
                pCur->next->pre = pCur->pre;
            }
            pCur->pre->next = pCur->next;
            pPre = pCur; 
            pCur = pCur->next;
            free(pPre);
            count ++;
        } else {
            pPre = pCur;
            pCur = pCur->next;
        }
    }
    return count; 
}

/* 链表求长 */
int get_List_Length(struct DouLinkNode *head)
{
    struct DouLinkNode *p;
    int len = 0;
    p = head;
    for (p; p->next!=NULL; p=p->next) {
        len++;
    }
    return len;
}

/* 双向链表排序 */
struct DouLinkNode *sort(struct DouLinkNode *head)
{
    struct DouLinkNode *p,*s,*min;
    int tmp;

    for(p = head->next ;p->next!=NULL ;p=p->next) {
        min = p ;
        for(s= p->next ; s!=NULL ;s=s->next) {
            if(s->data <min->data)
                min = s;               //找到每次排序中最小的节点，然后记住这个节点
        } if(min != p) {               //把这个节点与前面的节点的数据进行交换，把最小的数据放在前面的节点内。
            tmp = min->data;
            min->data = p->data;
            p->data = tmp;
        }
    }
    return head;
}
void main()
{
    struct DouLinkNode  *head,*head1;
    int n;
    int data;
    printf("input n:");
    scanf("%d",&n);
    head = create(n);
    display(head);
    printf("insert node from head: data=");
    scanf("%d", &data);
    insertListHead(head, data);
    display(head);
    printf("insert node from tail: data=");
    scanf("%d", &data);
    insertListTail(head, data);
    display(head);
    insertList(head, 5555, 4);
    display(head);
    printf("please input the data you want to delete: data=");
    scanf("%d", &data);
    int k = deleteListNode(head, data);
    printf("success! delete nodes:%d\n ", k);
    display(head);
    printf("the list length:%d\n", get_List_Length(head));
    head1 = sort(head);
    display(head1);
}

运行结果如下所示：