链表——用C++模板实现

LinkedList.h

//单向链表的实现//查找、插入和移除某个元素、复制、清空单向链表的时间复杂度均为O(n)//设计类时，应尽量减少类的成员函数之间的依赖关系#ifndef LINKEDLIST_H#define LINKEDLIST_Htemplate<class DT>struct Node{DT info;Node<DT> *next;};template<class DT>class LinkedList{public:LinkedList();LinkedList(const LinkedList<DT> &aplist);~LinkedList();LinkedList<DT>& operator=(const LinkedList<DT> &rlist);void insert(const DT &element); //在链表的头部之前插入void insert_end(const DT &element); //在链表的尾部插入bool first(DT &listEl); //得到对头的数据inline bool getNext(DT &listEl); //得到当前指针所指的下一个数据bool find(const DT &element); //查找一个数据bool retrieve(DT &element); //检索一个数据bool replace(const DT &newElement); //更改一个数据bool remove(DT &element);bool isEmpty() const;void makeEmpty();private:Node<DT> *start; //指向头结点Node<DT> *current; //指向当前的结点inline void deepCopy(const LinkedList<DT> &original); //"深复制"};#endif 

LinkedList.cpp

#include "LinkedList.h"template<class DT>LinkedList<DT>::LinkedList(){start = current = NULL;}template<class DT>LinkedList<DT>::LinkedList(const LinkedList<DT> &aplist){deepCopy(aplist);}template<class DT>LinkedList<DT>::~LinkedList(){makeEmpty();}template<class DT>LinkedList<DT>& LinkedList<DT>::operator =(const LinkedList<DT> &rlist){if(this == &rlist)return this;makeEmpty();deepCopy(rlist);return this;}//在链表的表头插入DT &element，插入后没有当前位置template<class DT>void LinkedList<DT>::insert(const DT &element){current = NULL;Node<DT> *NNode = new Node<DT>;NNode->info = element;NNode->next = start;start = NNode;}////在链表的尾部插入template<class DT>void LinkedList<DT>::insert_end(const DT &element){current = NULL;Node<DT> *NNode = new Node<DT>;NNode->info = element;NNode->next = NULL;Node<DT> *temp;DT item;if(start == NULL){start = NNode;temp = start;return;}temp = start;while(temp->next != NULL){temp = temp->next;}temp->next = NNode;}//把链表中的第一个元素存放在listEl中，并且把第一个元素的位置置为currenttemplate<class DT>bool LinkedList<DT>::first(DT &listEl){if(start == NULL)return false;current = start;listEl = start->info; return true;}//把链表中current的下个元素放在listEl中，current指向下一个元素template<class DT>bool LinkedList<DT>::getNext(DT &listEl){if(current == NULL)return false;if(current->next == NULL){current = NULL;return false;}listEl = current->next->info;current = current->next;return true;}//如果找到elment，返回true,current在getNext()中设置template<class DT>bool LinkedList<DT>::find(const DT &element){DT item;if(!first(item))return false; //检查是否为空do{if(item == element)return true;}while(getNext(item));return false;}template<class DT>bool LinkedList<DT>::retrieve(DT &element){if(!find(element))return false;element = current->info;return true;}template<class DT>bool LinkedList<DT>::replace(const DT &newElement){if(current == NULL)return false;current->info = newElement;return true;}template<class DT>bool LinkedList<DT>::remove(DT &element){current = NULL;if(start == NULL)return false;Node<DT> *ptr = start;if(start->info == element){element = start->info;start = ptr->next;delete ptr;return true;}while(ptr->next != NULL){if(ptr->next->info == element){Node<DT> *tempptr = ptr->next;element = tempptr->info;ptr->next = tempptr->next;delete tempptr;return true;}ptr = ptr->next;}return false;}template<class DT>bool LinkedList<DT>::isEmpty() const{ return start == NULL;}template<class DT>void LinkedList<DT>::makeEmpty(){while(start != NULL){current = start;start = start->next;delete current;}current = NULL;}template<class DT>void LinkedList<DT>::deepCopy(const LinkedList<DT> &original){start = current = NULL;if(original.start == NULL)return;Node<DT> *copyptr = start = new Node<DT>;Node<DT> *originalptr = original.start;copyptr->info = originalptr->info;if(originalptr == original.current)current = copyptr;while(originalptr->next != NULL){copyptr->next = new Node<DT>; //这一句有难度啊！originalptr = originalptr->next;copyptr = copyptr->next;copyptr->info = originalptr->info;if(originalptr == original.current)current = copyptr;}copyptr->next = NULL;}//#endif 

测试用例：

#include<iostream>#include "LinkedList.cpp"#include<string>using namespace std;void main(){string str[5] = {"hello","world","welcome","to","beijing"};//初始化一个链表LinkedList<string> strLL;for(int ix=0;ix<5;++ix)//strLL.insert(str[ix]); //调用insert()，依次插入在链表的头部 strLL.insert_end(str[ix]);//遍历链表cout<<"遍历链表: ";string listEl;if(strLL.first(listEl))cout<<listEl<<" "; //获得currentwhile(strLL.getNext(listEl))cout<<listEl<<" ";cout<<endl;LinkedList<string> strLL2(strLL); //调用构造函数初始化LinkedList<string> strLL3 = strLL; //调用重载“=”操作符 strLL2.first(listEl);cout<<"ListEl = "<<listEl<<endl;strLL3.first(listEl);cout<<"ListEl = "<<listEl<<endl;if(strLL2.find(str[3])) //调用find()cout<<"str[3] = "<<str[3]<<endl;if(strLL3.retrieve(str[2])) //调用retrieve()cout<<"str[2] = "<<str[2]<<endl;if(strLL.remove(str[1])){strLL.first(listEl); cout<<"ListEl after remove is "<<listEl<<endl;}if(strLL.isEmpty())cout<<"List is Empty!"<<endl;strLL.makeEmpty();strLL2.makeEmpty();strLL3.makeEmpty();cout<<"hello"<<endl;}