双向链表插入删除基本应用介绍

struct DNode
{
int data;
struct DNode *next;
struct DNode *pre;
};

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struct DNode
{
int data;
struct DNode *next;
};

#ifndef HEAD_H
#define HEAD_H
#include <iostream>
using namespace std;
#include <cassert>
#include <cstdlib>
#include <cmath>
#include <sstream>
#include <fstream>
#include <string>
#include <algorithm>
#include <list>
#include <queue>
#include <vector>
#include <deque>
#include <stack>
#include <bitset>
#include <set>
#include <map>
#endif
struct DNode
{
int data;
struct DNode *next;
struct DNode *pre;
};
DNode *Creat()
{ 
DNode *head,*p,*s;
head=(DNode *)malloc(sizeof(DNode));
p=head;
int temp;
while (cin>>temp&&temp)
{
s=(DNode *)malloc(sizeof(DNode));
s->data=temp;
p->next=s;
s->pre=p;
p=s;
}
head=head->next;
p->next=NULL;
head->pre=NULL;
return (head);
}
DNode *Insert(DNode *&head,int num)
{
DNode *p,*s;
s=(DNode *)malloc(sizeof(DNode));
s->data=num;
p=head;
while (NULL!=p->next&&num>p->data)
{
p=p->next;
}
if (num<=p->data)
{
if (NULL==p->pre)
{
s->next=head;
head->pre=s;
head=s;
head->pre=NULL;
}
else
{
s->pre=p->pre;
p->pre->next=s;
s->next=p;
p->pre=s;
}
}
else
{
p->next=s;
s->pre=p;
s->next=NULL;
}
return(head);
}
DNode *Del(DNode *&head,int num)
{
DNode *p;
p=head;
while (NULL!=p->next&&num!=p->data)
{
p=p->next;
}
if (num==p->data)
{
if (NULL==p->pre)
{
head=p->next;
p->next->pre=head;
free(p);
}
else if (NULL==p->next)
{
p->pre->next=NULL;
free(p);
}
else
{
p->pre->next=p->next;
p->next->pre=p->pre;
free(p);
}
}
else
{
cout<<num<<" cound not be found"<<endl;
}
return head;
}
void Display(DNode *head)
{
DNode *p;
p=head;
while (NULL!=p)
{
cout<<(p->data)<<" ";
p=p->next;
}
cout<<endl;
}

#include "head.h"
int main()
{
DNode *head;
head=Creat();
Display(head);
#ifndef DEBUG
cout<<"please input an num to insert:";
#endif
int insert_num;
while (cin>>insert_num&&insert_num)
{
Insert(head,insert_num);
Display(head);
}
#ifndef DEBUG
cout<<"please input an number to delete:";
#endif
int delete_num;
while (cin>>delete_num&&delete_num)
{
Del(head,delete_num);
Display(head);
}
return (EXIT_SUCCESS);
}