C语言实例200（程序中有详细的注释和说明）

#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); }