双链表基本操作 doubly linked list

    #include<stdio.h>    
    #include<stdlib.h>   
    typedef struct doubleLink    
    {    
        int data;    
        struct doubleLink *pre;    
        struct doubleLink *next;    
    }dnode;    

    //建立链表     
    dnode* createDLink()    
    {    
        dnode *head,*p,*s;    
        int x;    
        head = (dnode*)malloc(sizeof(dnode));    
        p = head;    
        while(1)    
        {    
            printf("please input the data: ");    
            scanf("%d",&x);    
            if(x != 0)    
            {    
                s = (dnode*)malloc(sizeof(dnode));    
                s ->data = x;    
                s-> pre = p;    
                p->next = s;    
                p=s;    
            }    
            else    
                break;    
        }    
        p->next = NULL;    
        head = head ->next;    
        head->pre = NULL;    
        return head;    
    }    

    //顺序、反序打印链表     
    void printDLink(dnode *head)    
    {    
        dnode *p,*s;    
        p = head;    
        printf(" left to right: \n");    
        while(p)    
        {    
            printf("%d  ",p->data);    
            s = p;  //为了到达链表的末尾   
            p = p->next;    
        }    
        printf("\n right to left: \n");    
        while(s)    
        {    
            printf("%d  ",s->data);    
            s = s->pre;    
        }    
        printf("\n \n");    
    }    

    //删除一个结点     
    dnode* deletedNode(dnode *head,int i)    
    {    
        dnode *p;    
        p = head;    
        if(p->data == i)    
        {    
            head = p->next;    
            head->pre = NULL;    
            free(p);    
            return head;    
        }    

        while(p)    
        {    
            if(p->data == i)    
            {    
                p->pre->next = p->next;    
                p->next->pre = p->pre;    
                free(p);    
                return head;    
            }    
            p = p->next;    
        }    

        printf("data not found \n");    
        return head;    
    }    

    //插入一个结点     
    dnode* insertdNode(dnode *head,int i)    
    {    
        dnode *p,*temp;    
        p = head;    

        temp = (dnode*)malloc(sizeof(dnode));    
        temp ->data = i;    

        if(i < p->data)    
        {    
            head = temp;    
            head->next = p;    
            head->pre = NULL;    
            p->pre = head;    
            return head;    
        }    

        while(p != NULL && i > p->data)    
        {    
           p = p->next;  
        }  
        if(i < p->data)  
        {  
            temp ->next = p;  
            temp ->pre = p->pre;  
            p ->pre->next = temp;  
            p ->pre = temp;  
            return head;  
        }else  
        {  
            p->next = temp;  
            temp ->pre = p;  
            temp ->next = NULL;  
            return head;  
        }  
    }  


    int  main()    
    {    
        dnode *head;    
        head = createDLink();    
        printDLink(head);    

        head = insertdNode(head,4);  
        head = deletedNode(head,3);    
        printDLink(head);    
        return 0;  
    }    

转载自http://blog.csdn.net/acm_jl/article/details/50949777