#include #includetypedefintElemType;

typedefstructDLNode{

ElemType data;struct DLNode *next;struct DLNode *prior;

}DLNode;

DLNode*InitList(DLNode *DL);//初始化

int ListEmpty(DLNode *DL);//判空

int ListLength(DLNode *DL);//返回链表长度

int ListInsert(DLNode *DL, int i, ElemType e);//插入元素

int ListDelete(DLNode *DL, int i);//删除第i个元素

void TraverseList(DLNode *DL);//遍历线性表//初始化

DLNode* InitList(DLNode *DL){intx;

DLNode*p =NULL;

DLNode*r =NULL;

DL= (DLNode *)malloc(sizeof(DLNode));

DL->next =DL;

DL->prior =DL;

r=DL;

printf("输入直到-1为止\n");while(1){

scanf("%d", &x);if(x == -1){

printf("初始化成功\n");break;

}

p= (DLNode *)malloc(sizeof(DLNode));if(p){

p->data =x;

p->prior =r;

p->next =DL;

r->next =p;

DL->prior =p;

r=p;

}else{

printf("空间不足初始化失败\n");returnNULL;

}

}returnDL;

}//判空

int ListEmpty(DLNode *DL){return (DL->next ==DL);

}//插入元素

int ListInsert(DLNode *DL, inti, ElemType e){if(i>ListLength(DL)+1 || i<=0){

printf("插入位置有误，插入失败\n");return 0;

}

DLNode*p =DL;int j = 0;while(j

p= p->next;

j++;

}

DLNode*nDLNode = (DLNode *)malloc(sizeof(DLNode));

nDLNode->data =e;

nDLNode->prior = p->prior;

p->prior->next =nDLNode;

p->prior =nDLNode;

nDLNode->next =p;

printf("插入成功\n");return 1;

}//删除第i个元素

int ListDelete(DLNode *DL, inti){if(i>ListLength(DL) || i<=0){

printf("删除位置有误，插入失败\n");return 0;

}

DLNode*p =DL;int j = 0;while(j

p= p->next;

j++;

}

p->prior->next = p->next;

p->next->prior = p->prior;free(p);

printf("删除成功\n");return 1;

}//返回链表长度

int ListLength(DLNode *DL){int len = 0;if(ListEmpty(DL)) return 0;

DLNode*p = DL->next;while(p->data!=DL->data){

len++;

p= p->next;

}returnlen;

}//遍历线性表

void TraverseList(DLNode *DL){if(ListEmpty(DL)){

printf("空链表");

}

DLNode*p = DL->next;//终止循环遍历

while(p->data != DL->data){

printf("%d", p->data);

p= p->next;

}

printf("\n");

}intmain(){

ElemType e=NULL;

DLNode*DL =NULL;//初始化测试

DL =InitList(DL);// //等价测试//DLNode *d = DL->next->next;//if(d->next->prior == d->prior->next){//printf("d->next->prior == d->prior->next\n");//}//if(d->next->prior == d){//printf("d->next->prior == d\n");//}//if(d == d->prior->next){//printf("d == d->prior->next\n");//}//遍历测试

TraverseList(DL);//

//printf("双向循环链表长度为%d\n",ListLength(DL));//插入元素测试

printf("第3个位置插入999\n");

ListInsert(DL,3, 999);

TraverseList(DL);//-----------------------------------------------------//非法操作?循环双向链表插入一个巨大的位置是否合法？//和老师讨论完，算不合法

printf("第567位置插入999\n");

ListInsert(DL,567, 999);

TraverseList(DL);//------------------------------------------------------//删除元素测试//printf("删除第1个位置\n");//ListDelete(DL, 1);//TraverseList(DL);//------------------------------------------------------//非法操作?同上//新问题，1，2，3，4，-1，删除第5个是头节点。//和老师讨论完，算不合法//printf("删除第55位置\n");//ListDelete(DL, 55);//TraverseList(DL);//------------------------------------------------------

}