循环双链表的删除、插入、显示

<span style="font-size:18px;">#include <stdio.h>#include <stdlib.h>#include <Windows.h>typedef int ItemValue;const int sleep_time = 10000;typedef struct DoubleLinkedList{ItemValue value;struct DoubleLinkedList *pre;struct DoubleLinkedList *next;} DoubleList, *pDoubleList;DoubleList *CreateCylicDoubleLinkedList(){printf("创建循环双链表!\n");DoubleList *head = (DoubleList *)malloc(sizeof(DoubleList));head->pre = head;head->next = head;DoubleList *pTemp;pTemp = head;ItemValue iValue;while (scanf("%d", &iValue) != EOF){DoubleList *p = (DoubleList *)malloc(sizeof(DoubleList));p->value = iValue;p->pre = pTemp;p->next = head;pTemp->next = p;pTemp = p;head->pre = p;}return head;}#if 0/* 访问循环双链表 */void VisitCylicDoubleLinkedList(DoubleList *dl){printf("循环双链表的输出!\n");DoubleList *pTemp;pTemp = dl;while (pTemp->next != dl){printf("%d ", pTemp->next->value);pTemp = pTemp->next;}}#endif#if 1/* 访问循环双链表 */void VisitCylicDoubleLinkedList(DoubleList *dl){printf("循环双链表的输出!\n");DoubleList *pTemp;pTemp = dl;pTemp = pTemp->next;while (pTemp != dl){printf("%d ", pTemp->value);pTemp = pTemp->next;}}#endif/* 删除元素 */void DeleteCylicDoubleLinkedList(DoubleList *L, int pos){printf("\n删除位置为%d上的元素\n", pos);if (L == NULL) {printf("链表为空!\n");Sleep(sleep_time);exit(1);}if (pos <= 0) {printf("\n删除位置不合理! 必须从第1个结点开始\n");Sleep(sleep_time);exit(1);}DoubleList *pTemp;pTemp = L;pTemp = pTemp->next;int i=1;while (pTemp != L && i!=pos){pTemp = pTemp->next;i++;}if (pTemp == L) {printf("\n删除结点不在链表中！\n");Sleep(1000);exit(1);}else {pTemp->next->pre = pTemp->pre;pTemp->pre->next = pTemp->next;}}/* 在位置i之后插入元素value */void InsertItemInDoubleLinkedList(DoubleList *L, ItemValue iValue, int pos){if (L == NULL){printf("\n插入链表为空! \n");}if (pos <= 0) {printf("\n插入位置不合理! \n");Sleep(sleep_time);exit(1);}DoubleList *pInsert = (DoubleList *)malloc(sizeof(DoubleList));pInsert->value = iValue;DoubleList *pTemp;pTemp = L;int i = 0; //插入元素前一个结点标号while (pTemp->next != L && i != pos-1){pTemp = pTemp->next;i++;}if (pTemp->next != L && i==pos-1){pInsert->next = pTemp->next;pTemp->next->pre = pInsert;pInsert->pre = pTemp;pTemp->next = pInsert;return;}if (pTemp->next == L && i==pos-1){pInsert->next = pTemp->next;pInsert->pre = pTemp;L->pre = pInsert;pTemp->next = pInsert;}else{printf("\n插入位置超出链表!\n");Sleep(sleep_time);exit(1);}}int main(){DoubleList *DL;DL = CreateCylicDoubleLinkedList();VisitCylicDoubleLinkedList(DL);DeleteCylicDoubleLinkedList(DL, 5);VisitCylicDoubleLinkedList(DL);InsertItemInDoubleLinkedList(DL, 100, 4);VisitCylicDoubleLinkedList(DL);free(DL);system("pause");return 0;}</span>

其中循环双链表的插入操作，不简练，还没想到简洁方法，能够实现：首结点、中部结点、尾部结点插入操作