程序代码：

#include < stdio.h >
#include < stdlib.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,%f", &p1->num, &p1->score );
    }
    p2->next = NULL;
    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 );
}

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
    {
        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 );
}



    void main ( )
    {
        struct student *head, stu;
        long del_num;
        printf ( "input records:\n" );
        head = creat ( );
        print ( head );
        printf ("\ninput the deleted number:" );
        scanf ( "%ld",&del_num );
        head = del ( head, del_num );
        print ( head );
        printf ( "\ninput the inserted record: " );
        scanf ( "%ld,%f", &stu.num, &stu.score );
        head = insert ( head, &stu );
        print ( head );
        system ( "pause" );
    }