关于链表的综合操作

学习过程中写的，就当复习基础知识好了。

#include<stdio.h>
#include<malloc.h>
#define LEN sizeof(struct student)
//#define NULL 0
struct student
{
 long num;
 float score;
 struct student *next;
};

int n;

struct student *creat(void)     /*创建动态链表*/
{
   struct student *p1,*p2,*head;
   p1=p2=(struct student *) malloc(LEN);
   scanf("%ld,%f",&p1->num,&p1->score);
   n=0;
   while(p1->num!=0)
   {
    n++;
    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)    //删除链表节点
{
    struct student *p1,*p2;
 if(head==NULL)
 {
  printf("空链表!/n");
  return head;
 }
 p1=head;
 while(p1->num!=num&&p1->next!=NULL)
 {
  p2=p1;
  p1=p1->next;
 }
 if(p1->num==num)
 { 
  if(p1==head)  head=p1->next;
  else p2->next=p1->next;
  printf("delete %d successfully!/n",num);
 }
 else printf("not found the num!");
 return head;
}

struct student *insert(struct student *head,struct student *stud)     //插入一个节点。
{
 struct student *p0,*p1,*p2;
 p1=head;
 p0=stud;
 if(head==NULL)
  head=p0,p0->next=NULL;
 else
 {
  while(((p0->num)>(p1->num))&&(p1->next!=NULL))
  {
   p2=p1;
   p1=p1->next;
  }
  if(p0->num<=p1->num)
  {
       if(p1==head) head=p0,p0->next=p1;
    else p2->next=p0,p0->next=p1;
  }
  else
  {
   p1->next=p0;
   p0->next=NULL;
  }
 }
 return head;
}
void main()
{
 long num;
 struct student *p,*head,stud;
    head=p=creat();
 do
 {
  printf("%ld,%.2f/n",p->num,p->score);
  p=p->next;
 }
 while(p!=NULL);
    printf("input the num you want to delete:/n");
 scanf("%ld",&num);
 p=del(head,num);
 do
 {
  printf("%ld,%.2f/n",p->num,p->score);
  p=p->next;
 }
 while(p!=NULL);
   
 printf("input the inserted record:/n");
    scanf("%ld,%f",&stud.num,&stud.score);
 p=insert(head,&stud);
    do
 {
  printf("%ld,%.2f/n",p->num,p->score);
  p=p->next;
 }
 while(p!=NULL);
}