C语言单向链表操作：创建和删除低于分数线节点

#include <stdio.h>
#include <stdlib.h>

struct stud_node {
    int              num;      /*学号*/
    char             name[20]; /*姓名*/
    int              score;    /*成绩*/
    struct stud_node *next;    /*指向下个结点的指针*/
};

struct stud_node *createlist() {
    struct stud_node *head, *tail, *p;
    head = (struct stud_node*)malloc(sizeof(struct stud_node));
    tail = head;
    scanf('%d', &tail->num);
    while (tail->num) {
        scanf('%s%d', tail->name, &tail->score);
        p = (struct stud_node*)malloc(sizeof(struct stud_node));
        tail->next = p;
        tail = p;
        scanf('%d', &tail->num);
    }
    tail->next = NULL;
    return head;
}

struct stud_node *deletelist(struct stud_node *head, int min_score) {
    struct stud_node *p = head, *q;
    while (p != NULL && p->score < min_score) {
        head = p->next;
        free(p);
        p = head;
    }
    while (p != NULL) {
        while (p->next != NULL && p->next->score < min_score) {
            q = p->next;
            p->next = q->next;
            free(q);
        }
        p = p->next;
    }
    return head;
}

int main() {
    int min_score;
    struct stud_node *p, *head = NULL;

    head = createlist();
    scanf('%d', &min_score);
    head = deletelist(head, min_score);
    for ( p = head; p != NULL; p = p->next )
        printf('%d %s %d\n', p->num, p->name, p->score);

    return 0;
}

输入样例：

1 zhang 78 2 wang 80 3 li 75 4 zhao 85 0 80

输出样例：

2 wang 80 4 zhao 85