c++ 实现双链表基本操作

#include <cstdlib>
#include <iostream>
#include <stdio.h>
#include <conio.h>
/*c++实现双链表的基本操作*/
using namespace std;
typedef struct student
{
int data;
struct student *pre;
struct student *next;
}dnode;
//创立链表
dnode *creat()
{
dnode *head,*p,*s;
int x,cycle=1;
head=(dnode *)malloc(sizeof(dnode));
p=head;
while(cycle)
{
cout<<"please input the data!"<<endl;
cin>>x;
if(x!=0)
{
s=(dnode *)malloc(sizeof(dnode));
s->data=x;
p->next=s;
s->pre=p;
p=s;
}
else
cycle=0;
}
head=head->next;
head->pre=NULL;
p->next=NULL;
return head;
}
//打印链表
void print(dnode *head)
{
dnode *p,*s;
p=head;
cout<<"正序打印双链表:"<<endl;
while(p->next!=NULL)
{
cout<<p->data<<" ";
p=p->next;
}
cout<<p->data<<endl;
cout<<"逆序打印双链表:"<<endl;
while(p->pre!=NULL)
{
cout<<p->data<<" ";
p=p->pre;
}
cout<<p->data<<endl;

}
//双链表插入节点
dnode *insert(dnode *head,int num)
{
dnode *p0,*p1;
p1=head;
p0=(dnode *)malloc(sizeof(dnode));
p0->data=num;
while(p0->data>p1->data&&p1->next!=NULL)
{
p1=p1->next;
}
if(p0->data<=p1->data)
{
if(head==p1)
{
p0->next=p1;
p1->pre=p0;
head=p0;
}
else
{
p1->pre->next=p0;
p0->next=p1;
p0->pre=p1->pre;
p1->pre=p0;
}
}
else
{
p1->next=p0;
p0->pre=p1;
p0->next=NULL;
}
return head;
}
//删除指定的节点
dnode *del(dnode *head,int num)
{
dnode *p1,*p2;
p1=head;
while(num!=p1->data&&p1->next!=NULL)
p1=p1->next;
if(num==p1->data)
{
if(p1==head)
{
head=head->next;
head->pre=NULL;
free(p1);
}
else if(p1->next==NULL)
{
p1->pre->next=NULL;
free(p1);
}
else
{
p1->next->pre=p1->pre;
p1->pre->next=p1->next;
free(p1);
}
}
else
{
cout<<"没有指定的节点"<<endl;
}
return head;
}
int main(int argc, char *argv[])
{
int x;
dnode *head=creat();
print(head);
cout<<"输入要插入的数字:"<<endl;
cin>>x;
head=insert(head,x);
print(head);
cout<<"输入要删除的数字:"<<endl;
cin>>x;
head=del(head,x);
print(head);
system("PAUSE");
return EXIT_SUCCESS;
}