c++ 链表的建立 插入 删除

[c++]代码库

#include "stdafx.h"
#include <iostream>
using namespace std;
//C++动态链表的建立
class Book
{
public:
	int num;
	int price;
	Book *next;
};
Book *p;
//创建头结点返回头结点地址给程序调用
Book* CreateHead()
{
	Book *head,*p1,*p2;//定义三个指向Book的类,返回值给head
	p1=new Book;
	head=p1;
	p2=p1;//将三个结点一起在椎中创建
	cout<<"请输入图书编号,以0结束"<<endl;
	cin>>p1->num;
	if ( p1->num!=0 )
	{
		cout<<"请输入图书价格"<<endl;
		cin>>p1->price;
	}
	else
	{
		delete p1;
		p2=NULL;
		return head;
	}
	while ( p1->num!=0 )
	{
		p2=p1;//这步很重要,意思为将P2设为当前结点，然后用p1继续创建，用培p2->next指向p1
		p1=new Book;
		cout<<"请输入图书编号,以0结束"<<endl;
		cin>>p1->num;
		if ( p1->num!=0 )
		{
			cout<<"请输入图书价格"<<endl;
			cin>>p1->price;
		}
		p2->next=p1;
	}
	delete p1;
	p2->next=NULL;
	return head;
}
void Show ( Book *head )
{
	while ( head!=NULL )
	{
		cout<<"图书编号为:"<<head->num<<",价格为:"<<head->price<<endl;
		head=head->next;
	}
}

//删除链表某个结点
void Delete ( Book *p,int num )
{
	Book *temp;
	if ( p->num==num )
	{
		temp=p;
		p=p->next;
		::p=p;
		delete temp;
		return;
	}
	while ( p )
	{
		if ( p->next==NULL )
		{
			cout<<"null"<<endl;
			return;
		}
		if ( p->next->num==num )
		{
			temp=p->next;
			p->next=temp->next;
			delete temp;
			cout<<"ok"<<endl;
			return;
		}
		p=p->next;
	}
	cout<<"null"<<endl;
}

//链表的添加(这里假设直接添加到最尾段)
void Insert ( Book *p,int num,int price )
{
	Book *temp=new Book;//这个结点用于添加编号和价格
	Book *tem=new Book;//这个结点用于存放尾结点地址
	while ( p )
	{
		tem=p;
		p=p->next;
	}
	temp->num=num;
	temp->price=price;
	tem->next=temp;
	temp->next=NULL;

}
int _tmain ( int argc, _TCHAR* argv[] )
{
	p=CreateHead();
	Show ( p );
	cout<<endl;
	cout<<"请输入要删除的编号"<<endl;
	int num;
	cin>>num;
	Delete ( p,num );
	Show ( p );
	cout<<"请输入编号"<<endl;
	cin>>num;
	int price;
	cout<<"请输入价格"<<endl;
	cin>>price;
	Insert ( p,num,price );
	Show ( p );
	system ( "pause" );
	return 0;
}