2302580027，游志新

[Youzhix]

#include <stdio.h>

typedef struct {
    int studentID;
    float score;
} Student;

int compare(const void *a, const void *b) {
    Student *studentA = (Student *)a;
    Student *studentB = (Student *)b;
    if (studentA->score < studentB->score) {
        return 1;
    } else if (studentA->score > studentB->score) {
        return -1;
    } else {
        return 0;
    }
}

int main() {
    int n; // 学生人数
    printf("请输入学生人数：");
    scanf("%d", &n);

    Student students[n]; // 学生数组

    for (int i = 0; i < n; i++) {
        printf("请输入第%d个学生的学号和成绩：", i + 1);
        scanf("%d%f", &students[i].studentID, &students[i].score);
    }

    qsort(students, n, sizeof(Student), compare);

    printf("按成绩由高到低的顺序输出学生的学号和成绩：\n");
    for (int i = 0; i < n; i++) {
        printf("学号：%d，成绩：%.2f\n", students[i].studentID, students[i].score);
    }

    float sum = 0;
    int count = 0;
    for (int i = 0; i < n; i++) {
        sum += students[i].score;
        if (students[i].score < 60) {
            count++;
        }
    }
    float average = sum / n;

    printf("平均成绩：%.2f\n", average);
    printf("不及格学生人数：%d\n", count);

    return 0;
}