跪求C语言大神帮我看看，这个程序错在哪里了，肿么老是错误错误啊……谢谢！

#include
#include
#define LEN sizeof(struct student)
struct student
{
long num;
float score;
struct student*next;
};
int n;
int main()
{
struct student *creat();//多了student，下同
struct student *del(student*,long);//同上
struct student *insert(student*,student*);//同上
void print(student*);
struct student*head,*stu;
long del_num;
printf("Input records:\n");
head=creat();
print(head);
printf("\nInput the deleted number:");
scanf("%ld",&del_num);
while(del_num!=0)
{
head=del(head,del_num);
print(head);
printf("Input the deleted number:");
scanf("%ld",&del_num);
}
printf("\nInput the inserted record:");
stu=(struct student*)malloc(LEN);
scanf("%ld,%f",&stu->num,&stu->score);
while(stu->num!=0)
{
head=insert(head,stu);
print(head);
printf("Input the inserted record:");
stu=(struct student*)malloc(LEN);
scanf("%ld,%f",&stu->num,&stu->score);
}
return 0;
}
struct student*creat()
{
struct student*head;
struct student*p1,*p2;
n=0;
p1=p2=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);//stu改为p1
head=NULL;
while(p1->num!=0)
{
n=n+1;
if(n==1)
head=p1;
else p2->next=p1;
p2=p1;
p1=(struct student*)malloc(LEN);
scanf("%ld,%f",&p1->num,&p1->score);
}
p2->next=NULL;
return(head);
}
struct student*del(struct student*head,long num)
{
struct student*p1,*p2;
if(head==NULL)
{
printf("\nlist null!\n");
return(head);
}
p1=head;
while(num!=p1->num&&p1->next!=NULL)
{
p2=p1;
p1=p1->next;
}
if(num==p1->num)
{
if(p1==head)
head=p1->next;
else p2->next=p1->next;
printf("delete:%ld\n",num);
n=n-1;
}
else
printf("%ld not been found!\n",num);
return(head);
}
struct student*insert(struct student*head,struct student*stud)
{
struct student*p0,*p1,*p2;
p1=head;
p0=stud;
if(head==NULL)
{
head=p0;
p0->next=NULL;
}
else//修改
while((p0->num>p1->num)&&p1->next!=NULL)
{
p2=p1;
p1=p1->next;
}
if(p0->numnum)//
{
if(head==p1)
head=p0;
else
p2->next=p0;
p0->next=p1;
}
else
{
p1->next=p0;
p0->next=NULL;
}
n=n+1;
return(head);
}
void print(struct student*head)
{
struct student*p;
printf("\nNow,These %d records are:\n",n);
p=head;
if(head!=NULL)
do
{
printf("%ld%5.1f\n",p->num,p->score);
p=p->next;
}
while(p!=NULL);
}