简单实现单链表

#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);}void Swap(SList& s){swap(_head, s._head);swap(_tail, s._tail);}SList&operator=(const SList& s){if (&s != this){SList tmp(s);Swap(tmp);}return *this;}void Destory(){if (_head == NULL)return;LinkNode* begin = _head;do{LinkNode* del = begin;begin = begin->_next;delete del;}while(begin != _head);_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){// 1.空链表// 2.有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.没有节点//2.一个节点//3.两个或两个以上的节点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){// 1.链表为空if (_head == NULL){_head = new LinkNode(x);_tail = _head;_tail->_next = _head;}else{LinkNode* tmp=new LinkNode(x);tmp->_next=_head;_head = tmp;_tail->_next=_head; }}void PopFront(){// 1.没有节点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;while(begin){if (begin->_data == x){return begin;}begin = begin->_next;if (begin == _head){break;}}return NULL;}bool Remove (LinkNode * n){assert(n);// 1.链表为空if (_head == NULL){return false;}// 2.只有一个节点if(_head == _tail){if (n == _head){delete _head;_head = NULL;_tail = NULL;return true;}return false;}// 3.两个以上的节点LinkNode* prev = _head;while (prev->_next != n){prev = prev->_next;// 如果没有找到n,则返回false。if (prev == _head){return false;}}if (n == _head){_head = _head->_next;delete n;_tail->_next = _head;}else if (n == _tail){prev->_next = _head;_tail = prev;delete n;}else{prev->_next = n->_next;delete n;}return true;}void Reverse(){if (_head == NULL)return;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;}void Insert (LinkNode * n, DataType x){if(_head == NULL){cout<<"链表为空,正在为您创建新链表"<<endl;_head = new LinkNode(x);_tail = _head;_tail->_next = _head;}else if(n == NULL){cout<<"找不到该节点，请重新输入节点插入"<<endl;return; }else if(_head == _tail){if(n == _head || n == _tail){LinkNode *tmp = _head;_head = new  LinkNode(x);_head->_next = tmp;_tail = tmp;_tail->_next = _head;}else{cout<<"找不到该节点，请重新输入节点插入"<<endl;return; }}else//两个以上节点{LinkNode* begin = _head;while(begin->_next != n){begin = begin->_next ;if(begin == _head)//没有找到该节点{cout<<"找不到该节点，请重新输入节点插入"<<endl;return ;}}if(n == _head){LinkNode *tmp = _head;_head = new LinkNode(x);_head->_next = tmp;_tail->_next = _head;}else if(n == _tail){LinkNode *tmp = _tail;_tail = new LinkNode(x);tmp->_next = _tail;_tail->_next = _head;}else{ LinkNode *tmp  = new LinkNode(x); begin->_next = tmp; tmp->_next = n;}}}void Erase (DataType x){LinkNode *begin = _head;LinkNode *tmp = begin;while(begin->_data != x){tmp = begin;begin = begin->_next ;if(begin == _head){cout<<"没有此元素，无法删除"<<endl;}}if(begin == _head){_head = _head->_next;_tail->_next = _head;}else if(begin == _tail){_tail = tmp;_tail->_next = _head;}else{tmp->_next = begin->_next ;}//delete tmp;//delete begin;}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.PopBack();s1.PopBack();s1.PopBack();s1.Print();}void Test2(){SList s1;s1.PushFront(1);s1.PushFront(2);s1.PushFront(3);s1.PushFront(4);s1.Print();s1.PopFront();s1.PopFront();s1.PopFront();s1.PopFront();s1.PopFront();s1.Print();}void Test3(){SList s1;s1.PushBack(1);//s1.PushBack(2);//s1.PushBack(3);//s1.PushBack(4);s1.Print();LinkNode* ret = s1.Find(1);cout<<"ret:"<<ret->_data<<endl;ret = s1.Find(5);cout<<"ret:"<<ret<<endl;}void Test4(){SList s1;s1.PushBack(1);s1.PushBack(2);s1.PushBack(3);s1.PushBack(4);s1.Print();SList s2;s2 = s1;s2.Print();s2.Reverse();s2.Print();}int main(){//Test1();//Test2();//Test3();Test4();system("pause");return 0;}