C++实现单向循环链表

#include<iostream>#include<assert.h>using namespace std;typedef int DataType;struct LinkNode{DataType _data;    LinkNode* _next;LinkNode(const DataType& x):_data(x),_next(NULL){}};class Slist{public:Slist():_head(NULL),_tail(NULL){}~Slist(){Destory();}Slist(const Slist& s):_head(NULL), _tail(NULL){if (s._head == NULL)return;LinkNode* begin = s._head;do{this->PushBack(begin->_data);begin = begin->_next;} while (begin != s._head);}Slist& operator = (const Slist& s){if (this != &s){this->Destory();LinkNode* begin = s._head;do{this->PushBack(begin->_data);begin = begin->_next;} while (begin != s._head);}return *this;}void Destory(){LinkNode* begin = _head;while (begin!=_tail){LinkNode* del = begin;begin = begin->_next;delete del;}delete _tail;_head = NULL;_tail = NULL;}public:void Print(){if (_head == NULL){return;}LinkNode* begin = _head;do{cout << begin->_data << "->";begin = begin->_next;}while (begin != _head);cout << endl;}void PushBack(const DataType& x)//尾插{//1.空链表//2.一个或一个以上节点if (_head == NULL){_head = new LinkNode(x);_tail = _head;_tail->_next = _head;}else {_tail->_next = new LinkNode(x);_tail = _tail->_next;_tail->_next = _head;}}void PopBack(){//1.空链表//2.只有一个节点//3两个或两个以上节点if (_head == NULL){return;}else if (_head == _tail){delete _head;_head = NULL;_tail = NULL;}else{LinkNode* prev = _head;while (prev->_next != _tail){prev = prev->_next;} prev->_next = _head;delete _tail;_tail = prev;}}void PushFront(const DataType& x){if (_head == NULL){_head = new LinkNode(x);_tail =_head ;_tail->_next = _head;}else{LinkNode* begin= new LinkNode(x);begin->_next = _head;_head = begin;_tail->_next = _head;}}void PopFront()//头删{if (_head == NULL){return;}else if (_head == _tail){delete _head;_head = NULL;_tail = NULL;}else{LinkNode* del = _head;_head = _head->_next;delete del;_tail->_next = _head;}}LinkNode* Find(DataType x){LinkNode* begin = _head;if (_head == NULL){return NULL;}do{if (begin->_data == x){return begin;}begin = begin->_next;}while(begin!=_head);return NULL;}bool Remove(LinkNode* n){assert(n);if (_head == NULL){return false;}    if (_head == _tail){if (n == _head){delete _head;    _head = NULL;    _tail = NULL;            return true;}return false;}LinkNode* prev = _head;while (prev->_next!=n){prev = prev->_next;if (prev = _head){return false;}}if (n == _head){_head = _head->_next;delete n;_tail->_next = _head;return true;}else if (n == _tail){prev->_next = _head;_tail = prev;delete n;return true;}else{prev->_next = n->_next;    delete n;    return true;}}void Reverse(){LinkNode* newHead=NULL, *newTail=_head;LinkNode* begin = _head;while (1){LinkNode* tmp = begin;begin = begin->_next;tmp->_next = newHead;newHead = tmp;if (begin == _head){break;}}_head = newHead;_tail = newTail;_tail->_next = _head;}bool Insert(LinkNode * n, DataType x){if (_tail <= n){return false;}else{LinkNode *begin = _head;do{begin = begin->_next;if (begin == _head){return false;}} while (begin->_next != n);begin->_next = n->_next;delete n;return true;}return false;}void Erase(DataType x){LinkNode* del = _head;do{del = del->_next;if (del->_data == x){do{del->_data = del->_next->_data;} while (del != _tail);}} while (del != _tail);}private:LinkNode* _head;//指向链表头的指针LinkNode* _tail;//指向链表尾的指针};void Test1(){Slist s1;s1.PushBack(1);s1.PushBack(2);s1.PushBack(3); s1.PushBack(4);s1.Print();/*s1.PopBack();s1.PopBack();s1.Print();*/Slist s2;s2 = s1;s2.Destory();s2.Print();}void Test2(){Slist s2;s2.PushFront(1);s2.PushFront(2);s2.PushFront(3);s2.Print();s2.Reverse();s2.Print();s2.PopFront();s2.Print();LinkNode* ret = s2.Find(2);cout << "ret=" << ret->_data << endl;}int main(){Test1();//Test2();system("pause");return 0;}