双向链表的删除

删除表中第i个元素

• 头结点及尾结点指针域的变化
• 查找过程中循环条件的变化
• 删除元素过程中的指针运算

如图：

程序；

#include<stdio.h>
#include<stdlib.h>
#define OK 1
#define ERROR 0
#define OVERFLOW 0
typedef struct DuLNode{
        int data;
        struct DuLNode *prior;
        struct DuLNode *next;
}DuLNode,*DuLinkList;
//建立一个只含头结点的空双向循环链表
int InitList_DuL(DuLinkList &L){
        L=(DuLinkList)malloc(sizeof(DuLNode));
        if(!L){
                exit(OVERFLOW);
        }
        L->prior=L;
        L->next=L;
        return OK;
}
int CreateList_DuL(DuLinkList &L,int n){
        DuLinkList p,q;
        int i;
        printf("Input the datas:");
        q=L;
        for(i=0;i<n;i++){
                p=(DuLinkList)malloc(sizeof(DuLNode));
                scanf("%d",&p->data);
                p->next=q->next;
//              p->next=L->next;
                q->next=p;
                p->prior=q;
                L->prior=p;
                q=p;
        }
                return OK;

}
int ListDelete_DuL(DuLinkList &L,int i,int &e){  //删除表中第i个元素，由变量e返回其值
        DuLinkList p;
        int j=1;
        p=L->next;
while(p!=L&&j<i){
                p=p->next;//查找第i个节点
                ++j;
        }
        while(p==L||j>i){
                return ERROR;
        }
        e=p->data;
        p->prior->next=p->next;
        p->next->prior=p->prior;
        free(p);
        return OK;


}
int TraverseList_DuL(DuLinkList L){//遍历
        DuLinkList p;
        p=L->next;
        while(p!=L){
                printf("%d",p->data);
                p=p->next;
        }
        return OK;
}
main(){
        int i,n,e;
        DuLinkList L;
        InitList_DuL(L);
        printf("Input the length of the list L:");
        scanf("%d",&n);
        CreateList_DuL(L,n);
        printf("Input the delete location:");
        scanf("%d",&i);
        if(ListDelete_DuL(L,i,e)){
                printf("Output the datas:");
                TraverseList_DuL(L);
        }else{
                printf("Can't delete the data!");
 　　}
        printf("\n");
}
结果：
android@android-Latitude-E4300:~/work/c/doublelianbiao$ ./listdelete
Input the length of the list L:5
Input the datas:1 3 5 7 9
Input the delete location:2
Output the datas:1579