双链表

双链表：

双向链表也叫双链表，是链表的一种，它的每个数据结点中都有两个指针，分别指向直接后继和直接前驱。所以，从双向链表中的任意一个结点开始，都可以很方便地访问它的前驱结点和后继结点。

双链表的一些基本操作函数的声明：

#include <stdio.h>#include <stdlib.h>#include <string.h>typedef struct Node {    int data;    struct Node * next;    struct Node * prior;}Node, *Pnode;Pnode create_list(void);    //创建节点void traverse_list(Pnode pHead);    //遍历链表打印 void fantraverse_list(Pnode pHead);int ListLength(Pnode pHead);Pnode ListInsert(Pnode pHead); Pnode ListDelete(Pnode pHead, int x);Pnode ListSort(Pnode pHead); void ListClear(Pnode pHead);

创建双链表的历程：

Pnode create_list(void){    int i, len;    Pnode pHead, pTemp;    pHead = (Pnode)malloc(sizeof(Node));    Pnode pNew;    if(NULL == pHead){        printf("内存分配出错！\n");        exit(1);    }     pHead = pTemp;    pTemp->next = NULL;    printf("请输入你想要的链表的长度：");    scanf("%d", &len);    for(i = 0; i < len; i++){        pNew = (Pnode)malloc(sizeof(Node));        if(NULL == pNew){            printf("新节点内存分配出错。\n");            exit(1);        }        printf("请输入新节点的值：");        scanf("%d", &pNew->data);        pTemp->next = pNew;        pNew->prior = pTemp;        pNew->next = NULL;        pTemp = pNew;    }    (pHead->next)->prior = NULL;    return pHead;}

由前向后遍历：

void traverse_list(Pnode pHead){    Pnode pTemp = pHead->next;     if(pTemp == NULL){        printf("链表为空。\n");    }    else{        printf("由前到后链表的值分别是：");        while(pTemp){            printf("%d ", pTemp->data);            pTemp = pTemp->next;        }    }    printf("\n"); }

由后向前遍历：

void fantraverse_list(Pnode pHead){    Pnode pTemp = pHead->next;    if(pTemp == NULL){        printf("链表为空。\n");        exit(1);    }    while(pTemp->next != NULL){        pTemp = pTemp->next;    }    printf("由后到前链表的值分别是：");    while(pTemp){        printf("%d ", pTemp->data);        pTemp = pTemp->prior;    }    printf("\n");}

插入历程：

Pnode ListInsert(Pnode pHead){    int x;    printf("请输入你想在那个值得前面或后面插：");    scanf("%d", &x);    Pnode pTemp = pHead->next;    Pnode pInsert, pTemp2;    while(pTemp && pTemp->data != x){        pTemp = pTemp->next;     }    if(pTemp == NULL){        printf("在链表中没有找到%d的值。\n", x);        return pHead;    }    else{        pInsert = (Pnode)malloc(sizeof(Node));        int s;        printf("请输入要插入元素的值：");        scanf("%d", &pInsert->data);        printf("请选择插在%d之前还是之后。(“0”前“1”后)", x);        do{             scanf("%d", &s);            if(s == 0){                if(pTemp->prior == NULL){                    pHead->next = pInsert;                    pTemp->prior = pInsert;                    pInsert->next = pTemp;                    pInsert->prior = NULL;                    break;                }                pTemp2 = pTemp->prior;                pInsert->next = pTemp;                pInsert->prior = pTemp2;                pTemp2->next = pInsert;                pTemp->prior = pInsert;            }            if(s == 1){                if(pTemp->next == NULL){                    pTemp->next = pInsert;                    pInsert->prior = pTemp;                    pInsert->next = NULL;                    break;                }                pTemp2 = pTemp->next;                pInsert->next = pTemp2;                pInsert->prior = pTemp;                pTemp->next = pInsert;                pTemp2->prior = pInsert;             }        }while(!(s == 0 || s == 1));    }    return pHead;}

删除历程：

Pnode ListDelete(Pnode pHead, int x){    Pnode pTemp = pHead;    while(pTemp->next && pTemp->next->data != x){        pTemp = pTemp->next;    }    if(pTemp->next == NULL){        printf("链表中没找到%d。\n", x);        return pHead;    }    Pnode pTemp2 = pTemp->next;    if(pTemp2 == pHead->next){        pHead->next = pTemp2->next;        (pTemp2->next)->prior = NULL;    }    else if(pTemp2->next == NULL){        pTemp->next = NULL;    }    else{        Pnode pTemp2 = pTemp->next;        pTemp->next = pTemp2->next;        (pTemp2->next)->prior = pTemp;    }    free(pTemp2);    return pHead;}

链表排序：

Pnode ListSort(Pnode pHead){    Pnode pFirst;    Pnode pMin;    Pnode pFmin;    Pnode pTail;    Pnode pTemp;    Pnode pTemp2;    if(pHead->next == NULL){         printf("链表为空！\n");        return pHead;    }    if(pHead->next->next == NULL){        printf("只有一组数据无需排序");    }    pFirst = NULL;     while(pHead->next != NULL){        for(pTemp = pHead, pMin = pHead->next; pTemp->next != NULL; pTemp = pTemp->next){            if(pMin->data > pTemp->next->data){                pFmin = pTemp;                pMin = pTemp->next;            }        }        if(pFirst == NULL){            pFirst = pMin;            pFirst->prior = NULL;            pTail = pMin;        }        else{            pTail->next = pMin;            pMin->prior = pTail;            pTail = pMin;        }        if(pHead->next == pMin)            pHead->next = pMin->next;        else            pFmin->next = pMin->next;    }    pTail->next  = NULL;    pHead->next = pFirst;    return pHead;}

销毁链表

void ListClear(Pnode Phead){    Pnode pTemp = Phead;    Pnode pTemp2;    while(pTemp != NULL){        pTemp2 = pTemp->next;        free(pTemp);        pTemp = pTemp2;    }}

一个测试 函数：

int main(void){    Pnode head = create_list();    traverse_list(head);    fantraverse_list(head);    printf("链表的长度是：%d\n", ListLength(head));     head = ListInsert(head);    traverse_list(head);    fantraverse_list(head);    int x;    printf("请输入你想删除的值：");    scanf("%d", &x);    head = ListDelete(head, x);    traverse_list(head);    fantraverse_list(head);     printf("排序后的链表：");    head = ListSort(head);    traverse_list(head);    fantraverse_list(head);    ListClear(head);    return 0;}

有几个函数没写^.^