//用一個函數建立一個有3名學生數據的單向動態鏈表
# include <stdio.h>
# include <malloc.h>
# define NULL 0
# define LEN sizeof(struct student)
struct student
{

    long num ;
    float score ;
    struct student *next ;

} ;
int n ;
struct student *creat(void)
{

    struct student *head ;
    struct student *p1 , *p2 ;
    n = 0 ;
    p1 = p2 = (struct student *)malloc(LEN) ;
    scanf("%ld,%f" , &p1->num ,&p1->score) ;
    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,%lf" , &p1->num , &p1->score) ;
    
    }
    p2->next = NULL ;
    return(head) ;

}