(续)线性表之双向链表(C语言实现)

在前文实现单向链表的基本操作下,本文实现双向链表的基本操作.

双向链表与单链表差异,是双向链表结点中有前向指针和后向指针.所以在插入和删除新结点元素时候不见要考虑后向指针还要考虑前向指针.

以下是双向链表的C代码:

#include<stdio.h>

typedef struct node
{
    int data;
    struct node *next;
    struct node *prior
}Node;

//链表的初始化
Node* InitList(int number)
{
    int i;
    Node *pHead=(Node *)malloc(sizeof(Node));
    Node *TempHead=pHead;
    Node *Head=pHead;
    Head->prior=NULL;
    int data;
    for(i=0;i<number;i++)
    {
        pHead=(Node *)malloc(sizeof(Node));
        printf("Please input the %dst node data:
",i+1);
        scanf("%d",&data);
        pHead->data=data;
        pHead->next=NULL;
        pHead->prior=TempHead;
        TempHead->next=pHead;
        TempHead=pHead;
    }
    return Head;
}

//显示链表
void ShowList(Node *Head)
{

    Head=Head->next;
    while(Head->next!=NULL)
    {
        printf("%d ",Head->data);
        Head=Head->next;
    }
    printf("%d",Head->data);
    printf("
");
}

//输出链表某个值的位置
int ListLocation(Node *Head,int data,int number)
{
    Node *TempNode=Head;
    int location=1;
    TempNode=TempNode->next;
    while(TempNode->next!=NULL)
    {
        if(TempNode->data==data)
            {
                return location;
            }
            location++;
            TempNode=TempNode->next;
    }
    if(location>=number)
        printf("Not found!");
}

//输出链表某个位置的值
int ListData(Node *Head,int location,int number)
{
    if(location>number)
        printf("Not found!");

    Node *TempNode=Head;
    TempNode=TempNode->next;
    int i;
    for(i=1;i<=number;i++)
    {
        if(location==i)
            return TempNode->data;
        TempNode=TempNode->next;
    }
}

//头入法插入元素
void HeadInsertData(Node *Head,int data)
{
    Node *InsertNode=(Node *)malloc(sizeof(Node));
    InsertNode->data=data;
    InsertNode->next=Head->next;
    Head->next->prior=InsertNode;
    Head->next=InsertNode;
    InsertNode->prior=Head;
}

//尾入插入除元素
void TailInsertData(Node *Head,int data)
{
    Node *TempNode=Head;
    Node *DeleteNode=(Node *)malloc(sizeof(Node));
    DeleteNode->data=data;
    while(TempNode->next!=NULL)
        TempNode=TempNode->next;

    TempNode->next=DeleteNode;
    DeleteNode->next=NULL;
    DeleteNode->prior=TempNode;

    free(DeleteNode);
}



//删除头结点
void HeadDeleteData(Node *Head)
{
    Head->next=Head->next->next;
    Head->next->prior=Head;
}


//删除尾结点
void TailDeleteData(Node *Head)
{
    Node *TempNode=Head;
    while(Head->next->next!=NULL)
        Head=Head->next;

    Head->next=NULL;
    Head->next->prior=NULL;
}

int main()
{
    Node *Head;
    int number;
    printf("Please input the node number:
");
    scanf("%d",&number);
    Head=InitList(number);
    printf("The initital list is:
");
    ShowList(Head);

    int flag;
    printf("

");
    printf("**********************Your Choice********************
");
    printf("****************1-输出链表某个值的位置***************
");
    printf("****************2-输出链表某个位置的值***************
");
    printf("****************3-头入法插入元素*********************
");
    printf("****************4-尾入法插入元素*********************
");
    printf("****************5-删除头结点*************************
");
    printf("****************6-删除尾结点*************************
");
    printf("****************0-退出*******************************
");
    printf("

");
    printf("Please input flag:
");
    scanf("%d",&flag);

    switch(flag)
    {
        case 1:
        {
            int data;
            printf("Please input the data you want locate:
");
            scanf("%d",&data);
            int location;
            location=ListLocation(Head,data,number);
            printf("The data's location is: %d",location);
            break;
        }
        case 2:
        {
            int location;
            printf("Please input the location you want  data:
");
            scanf("%d",&location);
            int data;
            data=ListData(Head,location,number);
            printf("The location's data is: %d
",data);
            break;
        }
        case 3:
        {
            int data;
            printf("Please input the data you want insert in head:
");
            scanf("%d",&data);
            HeadInsertData(Head,data);
            ShowList(Head);
            break;
        }
        case 4:
        {
            int data;
            printf("Please input the data you want insert in tail:
");
            scanf("%d",&data);
            TailInsertData(Head,data);
            ShowList(Head);
            break;
        }
        case 5:
        {
            HeadDeleteData(Head);
            ShowList(Head);
            break;
        }
        case 6:
        {
            TailDeleteData(Head);
            ShowList(Head);
            break;
        }
        case 7:
        {
           printf("You choose to exit.
");
           break;
        }
    }
    return 0;
}

结果图: