单向动态链表的建立、插入、删除、排序和保存

#include<iostream>
#include<fstream>
#include<string>
#include<iomanip>
using namespace std;
struct student
{
 int sID;
 string sName;
 student *next;
};
class LinkQueue
{
 public:
  LinkQueue();//构造空队列
  ~LinkQueue();//释放链队各节点的存储空间
  
  student *InQueue();//元素s从队尾入队
  student *addQueue(int num);//从第num个元素后入队 num=0就认为是从头指针前入队
  student *DeQueue(int num);//删除第num个元素
  student *OrderQueue();//把学号按从小到大排序
  void PrintfQueue();
     void save();
  student* read(char *filename);//待更新
 private:
  student *front;//队头指针
  student *rear;//队尾指针
  int lengthQueue;//链表长度
};
LinkQueue::LinkQueue()
{
 lengthQueue = 0;
 front = new student;
 front->next = NULL;
 rear = front;
}
LinkQueue::~LinkQueue()
{
 student *p;
 while (front != NULL)
 {
  p = front;
  front = front->next;
  delete p;
 }
}
student *LinkQueue::InQueue()
{
 student *p1, *p2;
 p1 = new student;
 front = p1;
 cout << "please input sID and sName:(end with sID=0)" << endl;
 cin >> p1->sID >> p1->sName;
 if (p1->sID == 0) front = NULL;
 while (p1->sID != 0)
 {
  p2 = new student;
  cout << "please input sID and sName:(end with sID=0)" << endl;
  cin >> p2->sID >> p2->sName;
  if (p2->sID == 0)
  {
   p1->next = NULL;
   
  }
  else
  {
   p1->next = p2;
  }
  //p3 = p1;
  p1 = p2;
  //rear = p3;
 }
 return front;
}
void LinkQueue::PrintfQueue()//把队列里的元素都打印
{
 student *pf;
 pf = front;
 while (pf != NULL)
 {
  cout << pf->sID << " " << pf->sName << endl;
  pf = pf->next;
  
 }
}
void LinkQueue::save()//关闭前保存所有的数据
{
 student *p;
 p = front;
 ofstream outfile("fl1.dat", ios::out);//ios::app 覆盖
 //ios::app 写入的数据添加到文件的末尾 
 //D:\学习资料\C++\自编程序\学生信息管理系统\学生信息管理系统
 if (!outfile)
 {
  cerr << "open error!" << endl;//cerr 把错误信息输出到控制台
  exit(1);
 }
 while (p != NULL)
 {
  outfile << "学号：" << p->sID << " " << "姓名：" << p->sName << endl;
  p = p->next;
 }
 outfile.close();
}

student *LinkQueue::DeQueue(int num)//num得小于链表的有效元素的长度
{
 student *p1,*p2,*p3;
 int count=1;
 p1 = front;
 if (num == 1)//删除头指针
 {
  p1 = front->next;
  front = p1;
 }
 else
 {
  while (count < num-1)
  {
   p1 = p1->next;
   count++;
  }
  p2 = p1;
  p3 = p1;
  p3 = p1->next;//p3指向待删除的元素
  p1 = p3->next;
  p3->next = NULL;
  p2->next = p1;
 }
 return front;
}
student *LinkQueue::addQueue(int num)
{
 student *p1, *p2,*p3;
 p2 = new student;
 int count = 1;
 p1 = front;
 cout << "please input the new sID and sName:" << endl;
 cin >> p2->sID >> p2->sName;
 if (num == 0)
 {
  front = p2;
  p2->next = p1;
 }
 else
 {
  while (count < num)
  {
   p1 = p1->next;
   count++;
  }
  p3 = p1->next;
  p1->next = p2;
  p2->next = p3;
 }
 return front;
}
student *LinkQueue::OrderQueue()//单向链表的排序
{
 student *p1,*p2,*p3;
 p3 = new student;
 p1 = front;
 p2 = p1->next;
 for (; p1->next != NULL;p1=p1->next)
 {
  for (p2 = p1->next; p2 != NULL; p2 = p2->next)
  {
   if (p2->sID < p1->sID)
   {
     p3->sID = p2->sID;
     p3->sName = p2->sName;
     p2->sID = p1->sID;
     p2->sName = p1->sName;
     p1->sID = p3->sID;
     p1->sName = p3->sName;
    
   }
  }
 }
 delete p3;
 return front;
}