双链表的创建、测长、打印、插入和删除

本文主要是介绍双链表的创建、测长、打印、插入和删除，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

内容RT，实现代码如下所示：

#include <iostream>
#include <stdio.h>
#include <string>using namespace std;typedef struct student
{int data;struct student *next;struct student *pre;
}dnode;// 建立双链表
dnode *creat()
{dnode *head, *p, *s;int x, cycle = 1;head = new dnode;p = head;while (cycle){cout << "Please input data for dnode : ";cin >> x;if (x != 0){s = new dnode;s->data = x;cout << x << endl;p->next = s;s->pre = p;p = s;} else{cycle = 0;}}head = head->next;head->pre = NULL;p->next = NULL;//cout << "Head data of dnode is " << head->data << endl;return head;
}//链表插入
dnode *Insert(dnode *head, int num)
{dnode *p0, *p1;p0 = new dnode;p0->data = num;p1 = head;while (p0->data > p1->data && p1->next != NULL){p1 = p1->next;}if (p0->data <= p1->data){if (p1 == head)// 头节点插入{p0->next = p1;p1->pre = p0;head = p0;} else//中间结点插入{p1->pre->next = p0;p0->next = p1;p0->pre = p1->pre; // 遗忘点p1->pre = p0;}} else// 尾部插入结点{p1->next = p0;p0->pre = p1;p0->next = NULL;}return head;
}// 双链表删除
dnode *del(dnode *head, int num)
{dnode *p1;p1 = head;while (num != p1->data && p1->next != NULL){p1 = p1->next;}if (p1->data == num){if (p1 == head)//首结点 head head->next {head = head->next;head->pre = NULL;delete p1;} else{if (p1->next == NULL)// 尾节点 p1->pre  p1  NULL{p1->pre->next = NULL;delete p1;} else//中间结点{p1->next->pre = p1->pre;p1->pre->next = p1->next;delete p1;}}} else{cout << "Please check out the data !" << endl;}return head;
}// 打印双链表
void PrintDL(dnode *head)
{dnode *p = head;int l = 0;while (p != NULL){p = p->next;l++;}cout << "The length of dnode is " << l << endl;p = head;for (int i = 0; i < l; i++){cout << "The dnode data is " << p->data << endl;p = p->next;}}int main()
{cout << "****创建双链表****" << endl;dnode *head = creat();cout << endl;cout << "****双链表测长和打印****" << endl;PrintDL(head);cout << endl;cout << "***双链表插入数据***" << endl;cout << "Please input the int data for ins operate : ";int Indata1 = 0;cin >> Indata1;head = Insert(head, Indata1);PrintDL(head);cout << endl;cout << "***双链表删除数据***" << endl;cout << "Please input the int data for del operate : ";int Indata2 = 0;cin >> Indata2;head = del(head, Indata2);PrintDL(head);cout << endl;return 0;
}

1.头结点插入和删除