int main()

{ student *creat(void);

  student *del(student *,long);  

  student *insert(student *,student *);

  void print(student *);

  student *head,*stu;

  long del_num;

  cout<<"input records:"<<endl;

  head=creat();                        //返回头指针

  print(head);                          //输出全部结点

  cout<<endl<<"input the deleted number:";

  cin>>del_num;                        //输入要删除的学号

  while(del_num!=0)

  {head=del(head,del_num);              //删除后链表的头地址

   print(head);                         //输出全部结点

   cout<<"input the deleted number:";

   cin>>del_num; 

  }

  cout<<endl<<"input the inserted record:";  //输入要插入的结点

  stu=new student;                      //开辟一个新结点

  cin>>stu->num>>stu->score;

  while(stu->num!=0)

  {head=insert(head,stu);              //返回地址

   print(head);                         //输出全部结点

   cout<<endl<<"input the inserted record:";  //输入要插入的结点

   stu=new student;

   cin>>stu->num>>stu->score;

  }

  return 0;

}

student *creat(void)       //建立链表的函数

{student *head;

 student *p1,*p2;

 n=0;

 p1=p2=new student;       //开辟一个新单元，并使 p1,p2 指向它

 cin>>p1->num>>p1->score;

3