用c++实现 c++单链表的实现（采用模板类）

函数实现数据的插入（头插&&尾插）、删除（头删&&尾删）、查找、按值插入、按值删除、求长、单链表清除、单链表摧毁、数据的逆置以及数据排序

#include"List.h"//单链表

void main()
{
List<int> mylist;
int select = 1;
int Item;
while(select)
{
cout<<"**************************************"<<endl;
cout<<"* [0] quit_system     [1] push_back  *"<<endl;
cout<<"* [2] push_front      [3] show_list  *"<<endl;
cout<<"* [4] pop_back        [5] pop_front  *"<<endl;
cout<<"* [6] insert_val      [7] delete_val *"<<endl;
cout<<"* [8] find            [9]length      *"<<endl;
cout<<"* [10] clear          [11]destroy    *"<<endl;
cout<<"* [12] reserv         [13]sort       *"<<endl;
cout<<"**************************************"<<endl;
cout<<"请选择:>";
cin>>select;
switch(select)
{
case 1:
cout<<"请输入要插入的值(-1结束):>";
while(cin>>Item, Item!=-1)
{
mylist.push_back(Item);
}
break;
case 2:
cout<<"请输入要插入的值(-1结束):>";
while(cin>>Item, Item!=-1)
{
mylist.push_front(Item);
}
break;
case 3:
mylist.show_list();
break;
case 4:
mylist.pop_back();
break;
case 5:
mylist.pop_front();
break;
case 6:
cout<<"请输入要插入的值:>";
cin>>Item;
mylist.insert_val(Item);
break;
case 7:
cout<<"请输入要删除的值:>";
cin>>Item;
mylist.delete_val(Item);
break;
case 8:
cout<<"请输入要查找的值:>";
cin>>Item;
mylist.find(Item);
break;
case 9:
mylist.length();
break;
case 10:
mylist.clear();
break;
case 11:
mylist.destroy();
break;
case 12:
mylist.reserv();
break;
case 13:
mylist.sort();
default:
break;
}
}
}

#ifndef _LIST_H
#define _LIST_H

#include<iostream>
using namespace std;

template<class Type>
class List;

template<class Type>
class ListNode
{
friend class List<Type>;
public:
ListNode():data(Type()),next(NULL)
{}
ListNode(Type d, ListNode<Type> *n=NULL)
:data(d),next(n)
{}
~ListNode()
{}
public:
void SetData(Type d)
{data = d;}
Type GetData()const
{return data;}
private:
Type data;
ListNode<Type> *next;
};

template<class Type>
class List
{
public:
List()
{
first = last = Buynode();
}
~List()
{
//destroy();
}
public:
void push_back(const Type &x);
void push_front(const Type &x);
void show_list();
void pop_back();
void pop_front();
void insert_val(const Type &x);
void delete_val(const Type &x);
int  length();
void clear();
void destroy();
void reserv();
void sort();
void find(const Type &x);
protected:
ListNode<Type>* Buynode(Type x = Type())
{
ListNode<Type> *p = new ListNode<Type>(x);
return p;
}
private:
ListNode<Type> *first;
ListNode<Type> *last;
};

template<class Type>
void List<Type>::push_back(const Type &x)//尾插
{
ListNode<Type> *s = Buynode(x);
last->next = s;
last = s;
first->data++;
}
template<class Type>
void List<Type>::push_front(const Type &x)//头插
{
ListNode<Type> *s = Buynode(x);
s->next = first->next;
first->next = s;
first->data++;
}

template<class Type>
void List<Type>::show_list()//显示
{
ListNode<Type> *p = first->next;
while(p != NULL)
{
cout<<p->data<<" ";
p=p->next;
}
cout<<endl;
}
template<class Type>
void List<Type>::pop_back()//尾删
{
while(first->data==0)
return;
ListNode<Type> *p = first;
while(p->next != last)
{
p = p->next;
}
delete p->next;
p->next = NULL;
last=p;
first->data--;
}
template<class Type>
void List<Type>::pop_front()//头删
{
ListNode<Type> *p = first->next;
ListNode<Type> *tmp = NULL;
if(first->data>0)
{
tmp = p->next;
first->next = tmp;
delete p ;
p = NULL;
first->data--;
}
}

template<class Type>
void List<Type>::insert_val(const Type &x)//按值插入
{
ListNode<Type> *s = Buynode(x);
ListNode<Type> *p = first->next;
if(p->data > s->data)
{
push_front(s->data);
}
else if(last->data < s->data)
{
push_back(s->data);
}
else
{
while(p!=NULL)
{
if(p->next->data>x)
{
s->next = p->next;
p->next = s;
first->data++;

return;
}
p=p->next;
}
}
}

template<class Type>
void List<Type>::delete_val(const Type &x)//按值删除
{
ListNode<Type> *p = first->next;
ListNode<Type> *tmp = NULL;
if(x == p->data)
{
pop_front();
return;
}
else if(last->data==x)
{
pop_back();
return;
}
else
{
while(p->next!=NULL)
{
if(p->next->data == x)
{
tmp = p->next;
p->next = tmp->next;
delete tmp;
first->data--;
return;
}
p = p->next;
}
}
}

template<class Type>
int List<Type>::length()//求长
{
cout<<first->data<<endl;
return first->data;
}

template<class Type>
void List<Type>::clear()//清除
{
while(first->data>0)
pop_front();
}

template<class Type>
void List<Type>::destroy()//摧毁链表
{
clear();
delete first;
first=last = NULL;
}

template<class Type>
void List<Type>::reserv()//逆序
{
ListNode<Type> *p = first->next;
ListNode<Type> *curr = p->next;
ListNode<Type> *tmp = NULL;

first->next->next = NULL;
while (curr)
{
tmp = curr->next;
curr->next = p;
p = curr;
curr = tmp;
}
first->next = p;
}

template<class Type>
void List<Type>::sort()//排序
{
ListNode<Type> *q = first->next;
while (q->next)
{
ListNode<Type> *p = q;
while(p->next)
{
if(q->data > p->next->data)
{
Type tmp =q->data;
q->data = p->next->data;
p->next->data = tmp;
}
p = p->next;
}
q = q->next;
}
}

template<class Type>
void List<Type>::find(const Type &x)//查找
{
ListNode<Type> *q = first->next;
int count = 0;
while(q !=NULL)
{
if(q->data == x)
{
count++;
}
q=q->next;
}
if(count)
cout<<"存在该值"<<endl;
else
cout<<"不存在该值"<<endl;
}

#endif