循环链表的实现

#include <iostream>

typedef int DataType;
typedef struct CirNode
{
DataType data;
CirNode* next;
};

typedef CirNode* CirLinkList;

// 创建循环链表
CirLinkList CreateCirLinkList()
{
CirNode* head = (CirNode*) malloc(sizeof(CirNode));
if (NULL == head)
{
std::cout << "Malloc memory failed ~" << std::endl;
exit(0);
}
CirNode* cur = head;

std::cout << "Input the linklist elem and -1 end" << std::endl;
DataType elem;

while( std::cin >> elem)
{
if (-1 == elem) break;
CirNode* node = (CirNode*) malloc(sizeof(CirNode));
if (NULL == node)
{
std::cout << "Malloc memory failed ~" << std::endl;
exit(0);
}

node->data = elem;
cur->next = node;
cur = node;
}

cur->next = head;
return head;
}

// 打印输出循环链表
void PrintCirLinkList(CirLinkList list)
{
if (NULL == list) return;
CirNode* cur = list->next;

std::cout << "CirLinkList elems [";
while(cur != list && cur != NULL)
{
std::cout << " " << cur->data;
cur = cur->next;
}

std::cout << " ]" << std::endl;
}

// 释放循环链表
void DestoryCirLinkList(CirLinkList list)
{
if (NULL == list) return;

CirNode* cur = list->next;
CirNode* next;

while(cur != list)
{
next = cur->next;
free(cur);
cur = next;
}
free(list);	   // 释放头结点
std::cout << "Destory cirlinklist successd " << std::endl;
}

// 查找循环链表
CirNode* FindCirNode(CirLinkList list,DataType val)
{
if (NULL == list) return NULL;
CirNode* cur = list->next;

while(cur != list)
{
if (cur->data == val)
return cur;
cur = cur->next;
}

return NULL;
}

// 在指定节点前插入新节点 成功返回1
int InsertCirNode(CirLinkList list, DataType val, DataType elem)
{
if (NULL == list) return -1;
CirNode* cur = list;

int flag = -1;
while (cur->next != list)
{
if (cur->next->data == val)
{
flag = 1;
break;
}
cur = cur->next;
}

if (-1 == flag) return -1;

CirNode* node = (CirNode*) malloc(sizeof(CirNode));
if (NULL == node) return 0;

node->data = elem;
node->next = cur->next;
cur->next = node;

return 1;
}

// 删除指定节点 执行成功返回1
int DeleteCirNode(CirLinkList list, DataType elem)
{
if (NULL == list) return -1;
CirNode* cur = list;

int flag = -1;
while (cur->next != list)
{
if (cur->next->data == elem)
{
flag = 1;
break;
}
cur = cur->next;
}

if (-1 == flag) return -1;

CirNode* tmp = cur->next;
cur->next = tmp->next;
free(tmp);

return 1;
}

int main()
{
CirLinkList list = CreateCirLinkList();
PrintCirLinkList(list);

DataType val, elem;
std::cout << "Input Find val " << std::endl;
std::cin >> val;

CirNode* node = FindCirNode(list, val);
if (NULL != node)
{
std::cout << "find node succeed " << node->data << std::endl;
}
else
{
std::cout << "Can't find node ~" << std::endl;
}

std::cout << "Input insert val and elem " << std::endl;
std::cin >> val >> elem;

if (int ans = InsertCirNode(list, val, elem) == 1)
{
std::cout << "Insert node succeed " << std::endl;
PrintCirLinkList(list);
}else
{
std::cout << "Insert node failed " << ans << std::endl;
}

std::cout << "Input delete elem " << std::endl;
std::cin >> elem;
if (1 == DeleteCirNode(list, elem))
{
std::cout << "Delete node succeed " << std::endl;
PrintCirLinkList(list);
}else
{
std::cout << "delete node failed " << std::endl;
}

DestoryCirLinkList(list);
return 0;
}