链表的实现（类模板）

#include<iostream>
#include<cstdlib>
#include<cstdio>
using namespace std;

template<class T>
class LinkList;    //类的声明

template<class T>
class ListNode{   //由于结构体不太便于描述，故此处使用类来描述结点
public:
friend class LinkList<T>;    //为了使LinkList类能访问该类的私有变量，应将其设为ListNode的友元类
//friend void f();
private:
T data;
ListNode<T>* next;
};

template<class T>
class LinkList{
public:
LinkList(){head = NULL;}   //构造函数，初始化链表
~LinkList(){};             //析构函数
bool ListEmpty(){return head == NULL;}
int ListLength();          //求链表长度
void CreateListF();        //头插法构造链表
void CreateListR();        //尾插法构造链表
void CreateList();         //带头结点的尾插法
bool GetElem(int i,T& x);  //判断第i个结点是否存在，若存在，将其记录在x中
int LocateElem(T x);       //求x所在的位置
void InsertNode(int i,T x);//在第i个元素前插入x
void DeleteNode(int i,T& x);//删除第i个元素，并将其记录在x中
void PrintList();          //打印该链表
//void f();
private:
ListNode<T>* head;
};

template<class T>
void LinkList<T>::CreateListF()
{
ListNode<T>* p = head,* s;
T ch;
ch = getchar();
while(ch != '\n'){         //换行符作为结束标志
s = new ListNode<T>;
s -> data = ch;
s -> next = p;
p = s;
ch = getchar();
}
head = p;
}

template<class T>
void LinkList<T>::CreateListR()
{
ListNode<T>* s,* rear = NULL;
T ch;
ch =getchar();
while(ch != '\n'){
s = new ListNode<T>;
s -> data = ch;
if(head == NULL)
head = s;
else
rear = s;
ch = getchar();
}
rear -> next = NULL;
}

template<class T>
void LinkList<T>::CreateList()
{
ListNode<T>* s,* rear = NULL;
T ch;
head = new ListNode<T>;
rear = head;
ch = getchar();
while(ch != '\n'){
s = new ListNode<T>;
s -> data = ch;
rear -> next = s;
rear = s;
ch = getchar();
}
rear -> next = NULL;
}

template<class T>
int LinkList<T>::ListLength()
{
ListNode<T>* p = head -> next;
int num = 1;
while(p){
p = p -> next;
num ++;
}
return num;
}

template<class T>
bool LinkList<T>::GetElem(int i, T& x)
{
int j = 1;
ListNode<T>* p = head -> next;
while(p && j < i){
p = p -> next;
j ++;
}
if(p){
x = p -> data;
return 0;
}
return -1;
}

template<class T>
int LinkList<T>::LocateElem(T x)
{
int num = 0;
ListNode<T>* p = head -> next;
while(p && p -> data != x){
num ++;
p = p -> next;
}
if(p)
return ++ num;
else
return -1;
}

template<class T>
void LinkList<T>::InsertNode(int i, T x)
{
ListNode<T>* p = head,* s;
int j = 0;
while(p && j < i - 1){
p = p -> next;
j ++;
}
if(i < 1 || i > ListLength() + 1)
return ;
s = new ListNode<T>;
s -> data = x;
s -> next = p -> next;
p -> next = s;
}

template<class T>
void LinkList<T>::DeleteNode(int i,T& x)
{
ListNode<T>* p = head,* u;
int j = 0;
while(p && j < i- 1){
p = p -> next;
j ++;
}
if(i < 1 || i > ListLength() + 1)
return;
u = new ListNode<T>;
u = p -> next;
p -> next = u -> next;
x = u -> data;
delete u;
}

template<class T>
void LinkList<T>::PrintList()
{
ListNode<T>* p = head -> next;
while(p){
cout<<p -> data<<" ";
p = p -> next;
}
cout<<endl;
}

int main()
{
LinkList<char>L;
char ch;
int k;
L.CreateList();
L.PrintList();
if(L.GetElem(8,ch) == 0)
cout<<"这个位置的元素是："<<ch<<endl;
else
cout<<"没有这个序号！"<<endl;
L.InsertNode(5,'t');
cout<<"在位置5插入t之后的内容如下：\n";
L.PrintList();
cout<<"删除位置5后的内容如下：\n";
L.DeleteNode(5,ch);
L.PrintList();
cout<<"被删除的元素是："<<ch<<endl;
ch = 'm';
k = L.LocateElem(ch);
if(k != -1)
cout<<"元素"<<ch<<"所在位置为："<<k<<endl;