程序员面试宝典——数据结构之双链表

#include<stdlib.h>
#include<iostream>
#include<stdio.h>
#include<string>
using namespace std;
typedef struct Node{
int data;
struct Node* next;
struct Node* pre;
}dnode;

dnode *create()
{
    dnode*head,*p,*s;
    int x,cycle=1;
    head=(dnode*)malloc(sizeof(dnode));
    p=head;
     cout<<"
Please input the data:"<<endl;
    while(cycle)
    {
        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;
    cout<<"
The head data is"<<head->data<<endl;
    return head;
}

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<<"could not been found "<<num<<endl;
    return head;
}

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->next;
            p1->pre=p0;
            head=p0;
        }
        else
        {
            p0->next=p1;
            p1->pre->next=p0;
            p0->pre=p1->pre;
            p1->pre=p0;
        }
    }
    else
    {
        p1->next=p0;
        p0->pre=p1;
        p0->next=NULL;
    }
    return head;
}

void print(dnode* head)
{    
    dnode* p=head;
    while(p->next!=NULL)
    {
        cout<<p->data<<"->";
        p=p->next;
    }
    cout<<endl;
}
int main()
{
    dnode *head,stud;
    int n,del_num,insert_num;
    head=create();
    print(head);
    cout<<"input delete number:";
    cin>>del_num;
    head=del(head,del_num);
    print(head);
    cout<<"please input the insert data:";
    cin>>insert_num;
    head=insert(head,insert_num);
    print(head);
    return 0;
}