单链表的基本操作--c++

 #include <iostream>     //实现单链表的建立，测长和打印
 #include <string>
 using namespace std;
 struct node            // 定义节点类型，包含一个数据域和一个指针域
 {
     int data;
     node *next;
 };
 node * creat()
 {
     node *head,*p,*s;   // p指针为当前的指针，s为新建结点的指针
     int temp,cycle = ;
     //head = (node*)malloc(sizeof(node));
     head = new node;
     p = head;
     while(cycle)
     {
         cout << "请输入int型数据" << endl;
         cin >> temp;
         if (temp != )             // 当temp不为零时，创建新的
         {
             //s = (node*)malloc(sizeof(node));
             s = new node;         //创建新的结点
             s -> data = temp;
             cout << "新节点为" << s -> data;
             p -> next = s;  // 使头结点的指针指向新生成的结点
             p = s;          //  使p指向当前新的结点
         }
         else
         {
             cout << "输入完成" <<endl;
             cycle = ;
         }
     }
     head = head -> next;      //头指针
     p -> next = nullptr;     //置最后一个结点的指针为空
     return head;
 }
 // 单链表测长
 int length(node *head)
 {
     int  n = ;
     node *p = head;
     while (p != nullptr )
     {
         p = p -> next;
         n++;
     }
     return n;
 }
 // 单链表打印
 void printlinklist(node * head)
 {
     node *p = head;
     while( p != nullptr)
     {
         cout << "data is" << p -> data << endl;
         p = p -> next;
     }
 }
 // 单链表插入
 node *insert(node * head, int num)
 {
     node *p0,*p1,*p2;
     p1 = head;
     p2 = new node;
     p0 = new node;// 插入结点
     p0 -> data = num;  // 插入数据
     // 若插入结点的数据大于原结点的数据，并且原结点的存在下一个元素
     while(p0 -> data > p1 -> data && p1 -> next != nullptr)
     {
         p2 = p1;
         p1 = p1 -> next;  // 这时  p2->p1->p0  ??
     }
     if (p0 -> data <= p1 -> data)
     {
         if ( p1 == head)
         {  //  头部前插入    p0和p1的位置是 P0->P1->
             head = p0;
             p0 -> next =p1;
         }
         else
         {  // 插入中间节点，   p2->p0->p1
             p2 -> next = p0;
             p0 -> next = p1;
         }
     }
     else
     {// 尾部插入结点，  p2->p1->p0->null
         p1 -> next = p0;
         p0 -> next = nullptr;
     }
     return head;
 }
 //删除单链表
 node *del(node *head, int num)
 {
     node *p1,*p2;
     p2 = new node;
     p1 = head;
     while(num != p1 -> data && p1 -> next != nullptr)
     {
         p2 = p1;
         p1 = p1 -> next;   //  p2->p1
     }
     if (num == p1->data)
     {
         if (p1 == head)  // 删除头结点
         {
             head =p1 -> next;
             delete p1;
         }
         else
         {
             p2 -> next = p1 -> next;
             delete p1;
         }
     }
     else
     {
         cout << "could not been found in current single linklist"<< endl;
     }
     return head;
 }
 int main()
 {

     cout << "创建单链表" << endl;
     node *head = creat();
     cout << endl;

     cout << "计算链表的长度" << endl;
     int n = length(head);
     cout << "the length of the linklist is " << n << endl;
     cout << endl;

     cout << "print the linklist" << endl;
     printlinklist(head);
     cout << endl;

     cout << "insert the node" << endl;
     cout << "please insert the data";
     int indata;
     cin >> indata;
     head = insert(head,indata);
     printlinklist(head);
     cout << endl;

     cout << "delete the node" << endl;
     cout << "input the data for deleting ";
     int deldata;
     cin >> deldata;
     head = del(head,deldata);
     printlinklist(head);
     cout <<endl;
     return ;
 }