我这有一个程序 使用结构体编写的  现在我想把它用类来实现 但是改了几次都有错误谁能 帮我改过来呢？
#define NULL 0
#define LEN sizeof(struct student)
#include "stdlib.h"
#include "stdio.h"
#include "string.h"
struct student
{
char name[10];
long int id;
int money;
struct student *next;
};
int n;
char ch[10];

/*******链表的建立********/
student *creat()
{
int i;
student *head,*p1,*p2;
n=0;
p1=p2=(struct student*)malloc(LEN);
  printf("请输入学生情况：依次为 姓名,学号,成绩（输入分号；结束)\n");
  printf("姓名:");
  scanf("%s",ch);
  head=NULL;
  while(strcmp(ch,";")!=0)
{
p1=(struct student*)malloc(LEN);
strcpy(p1->name,ch);
printf("学号:");
scanf("%ld",&p1->id);
printf("成绩:");
scanf("%d",&p1->money);
if(n==0)
head=p1;
else
p2->next=p1;
p2=p1;
n++;
printf("姓名:");
scanf("%s",ch);
}
p2->next=NULL;
return(head);
}

/******* 链表的输出*******/
void output(struct student *head)
{
struct student *p;
int i=0;
printf("\n输入％d个学生的记录：\n",n);
printf("序号         姓名         学号          成绩\n");
p=head;
if(head!=NULL)
do
{i++;
printf("%d\t %s\t %ld\t %d",i,p->name,p->id,p->money);
printf("\n");
p=p->next;
}
while(p!=NULL);
}

/*******链表的插入*******/
struct student *insert(struct student *head)
{struct student *p1,*p2,*p3;
printf("请输入新学生的情况！\n");
p1=(struct student*)malloc(LEN);
printf("姓名:");
scanf("%s",p1->name);
printf("学生学号:");
scanf("%ld",&p1->id);
printf("成绩：");
scanf("%d",&p1->money);
p2=head;
if(head==NULL)
{head=p1;
p1->next=NULL;
}
else
{
while((p1->id>p2->id)&&(p2->next!=NULL))
{ p3=p2;
p2=p2->next;
}
if(p1->id<p2->id)
{if(head==p2)
{p1->next=head;
head=p1;}
else
p3->next=p1;     p1->next=p2;
}
else
{p3->next=p1;
p1->next=p2;
}
}
n=n+1;
return(head);
}

/******链表的删除********/
struct student *delete(struct student *head,long int num)
{
  struct student *p1;
  printf("输入要删入的学生学号：%ld\n",num);
  if(head==NULL)
  {
    printf("\n这是一个空表，没有删除的结点！\n");
    return(head);
  }
  else
  p1=head;
   while(num!=p1->id&&p1->next!=NULL)
  {
   p1=p1->next;
  }
   if(num==p1->id);
     {if(p1==head)
      head=p1->next;
      else
     printf("删除学生学号为%ld的结点\n",num);
     n=n-1;
     }
   printf("没有找到学生学号为%ld的结点\n",num);
   return(head);
}


/*******主函数*******/
main()
{struct student *head, pers;
  long i;
  int k;
  do
  {
  printf("****************************\n");
  printf("1     建立全体学生档案\n");
  printf("2     输出全体学生档案\n");
  printf("4     添加学生档案\n");
  printf("5     删除学生档案\n");
  printf("6     退出本系统\n");
  printf("****************************\n");
  printf("请输入选择号(1--6)?");
  scanf("%d",&k);
  switch(k)
  {case 1:head=creat();
        break;
   case 2: printf("学生人数为：%d人\n");
     output(head);
     break;
  case 4:head=insert(head);
    printf("\n调整后学生人数为%d人\n");
    output(head);
    break;
   case 5:printf("请输入要删除学生的学号!\n");
    scanf("%ld",&i);
  head=delete(head,i);
output(head);
break;
}
} while(k!=6);
}