数据结构:双向链表list的表头/尾添加数据、链表显示、链表清空

#include<iostream.h>
//定义节点（数据对象）的接口
class Node
{
//声明list类为本类的友元类
friend class list;
//私有成员
private:
int Data;       //节点数据
Node *previous; //前趋指针
Node *next;     //后继指针
};

//定义双向链表list的接口声明
class list
{
//私有成员
private:
Node *Head;    //链表头指针
Node *Tail;    //链表尾指针
//定义接口函数
public:
//构造函数
list();
//析构函数
~list();
//从链表尾后添加数据
void Build_HT(int Data);
//从链表前头添加数据
void Build_TH(int Data);
//从头到尾显示数据
void list::Display_HT();
//从尾到头显示数据
void list::Display_TH();
//清除链表的全部数据
void Clear();
};

//main()函数测试双向链表
int main(void)
{
list list1;
int i;

//从尾添加数据
cout<<"Add to the back of the list1:"<<endl;
for (i=1;i<=20;i=i+2) {
list1.Build_HT(i);
cout<<i<<" ";
}
cout<<endl;

//从头添加数据
cout<<"Add to the front of the list1:"<<endl;
for (i=0;i<=20;i=i+2) {
list1.Build_TH(i);
cout<<i<<" ";
}
cout<<endl;

//显示链表
list1.Display_HT();
list1.Display_TH();

return 0;
}
//list类函数的定义
//构造函数的定义
list::list()
{
//初值
Head=0;
Tail=0;
}
//析构函数的定义
list::~list()
{
Clear();
}
//从链表尾后添加数据
void list::Build_HT(int Data)
{
Node *Buffer;

Buffer=new Node;
Buffer->Data=Data;
if(Head==0)
{
Head=Buffer;
Head->next=0;
Head->previous=0;
Tail=Head;
}
else
{
Tail->next=Buffer;
Buffer->previous=Tail;
Buffer->next=0;
Tail=Buffer;
}
}
//从链表前头添加数据
void list::Build_TH(int Data)
{
Node *NewNode;
NewNode=new Node;
NewNode->Data=Data;

if(Tail==0)
{
Tail=NewNode;
Tail->next=0;
Tail->previous=0;
Head=Tail;
}
else
{
NewNode->previous=0;
NewNode->next=Head;
Head->previous=NewNode;
Head=NewNode;
}
}
//从头到尾显示数据
void list::Display_HT()
{
Node *TEMP;
TEMP=Head;
cout<<"Display the list from Head to Tail:"<<endl;
while(TEMP!=0)
{
cout<<TEMP->Data<<" ";
TEMP=TEMP->next;
}
cout<<endl;
}
//从尾到头显示数据
void list::Display_TH()
{
Node *TEMP;
TEMP=Tail;
cout<<"Display the list from Tail to Head:"<<endl;
while(TEMP!=0)
{
cout<<TEMP->Data<<" ";
TEMP=TEMP->previous;
}
cout<<endl;
}
//清除链表的全部数据
void list::Clear()
{
Node *Temp_head=Head;

if (Temp_head==0) return;
do
{
Node *TEMP_NODE=Temp_head;
Temp_head=Temp_head->next;
delete TEMP_NODE;
}
while (Temp_head!=0);
}