#include<stdio.h>
#include"def.h"
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
		while((p0->num>p1->num)&&(p1->next!=NULL))
			{p2=p1;p1=p1->next;}
	if(p0->num<=p1->num)
		{
			if(head==p1) head=p0;
			else p2->next=p0;
			p0->next=p1;
		}
	else
		{p1->next=p0;p0->next=NULL;}
	n=n+1;
	return (head);
}