用c语言写出对一个有N个学生的班级，每个学生有3门课程，分别为语文，英语，数学。该系统实现对班级成绩的录入、显示、修改、排序、保存等操作的管理。功能要求： （1）本系统采用一个结构体数组，每个数据的结构应当包括：学号、姓名、M门课程名称。 （2）本系统显示这样的菜单： 系统功能选项： a、 数据导入及显示 b、新记录输入 c、 删除记录 d、成绩查询 e、 成绩修改（ 要求先输入密码） f、 成绩排序 （可按单科排序或按平均分排序） b、 成绩保存 c、 成绩统计 1）显示每门课程成绩最高的学生的基本信息 2）显示每门课程的平均成绩 3）显示超过某门课程平均成绩的学生人数 g、 退出系统 注意：需保证学号唯一性 （该题目用数组完成）

好的，以下是用C语言实现的班级成绩管理系统代码：

#include <stdio.h>
#include <string.h>

#define MAX_STUDENTS 100
#define MAX_NAME_LEN 20
#define MAX_ID_LEN 10
#define MAX_COURSE_NUM 3

typedef struct {
    char id[MAX_ID_LEN];
    char name[MAX_NAME_LEN];
    int score[MAX_COURSE_NUM];
} Student;

int num_students = 0;  // 学生总数
Student students[MAX_STUDENTS]; // 存储学生信息的数组

void print_menu();
void load_data();
void input_new_record();
void delete_record();
void query_score();
void modify_score();
int verify_password();
void sort_score();
void save_data();
void statistics();

int main() {
    char choice;

    while (1) {
        print_menu();
        scanf(" %c", &choice);

        switch (choice) {
            case 'a':
                load_data();
                break;
            case 'b':
                input_new_record();
                break;
            case 'c':
                delete_record();
                break;
            case 'd':
                query_score();
                break;
            case 'e':
                modify_score();
                break;
            case 'f':
                sort_score();
                break;
            case 'g':
                save_data();
                break;
            case 'h':
                statistics();
                break;
            case 'i':
                return 0;
            default:
                printf("Invalid choice, please choose again.\n");
        }
    }
}

void print_menu() {
    printf("系统功能选项：\n");
    printf("a、 数据导入及显示\n");
    printf("b、 新记录输入\n");
    printf("c、 删除记录\n");
    printf("d、 成绩查询\n");
    printf("e、 成绩修改\n");
    printf("f、 成绩排序\n");
    printf("g、 成绩保存\n");
    printf("h、 成绩统计\n");
    printf("i、 退出系统\n");
}

void load_data() {
    FILE *fp;
    char filename[100];

    printf("请输入数据文件名：");
    scanf("%s", filename);

    fp = fopen(filename, "rb");
    if (fp == NULL) {
        printf("打开文件失败！\n");
        return;
    }

    fread(&num_students, sizeof(num_students), 1, fp);
    fread(students, sizeof(Student), num_students, fp);

    printf("共读取到%d条记录：\n", num_students);
    for (int i = 0; i < num_students; i++) {
        printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
    }

    fclose(fp);
}

void input_new_record() {
    if (num_students >= MAX_STUDENTS) {
        printf("学生记录已满，无法录入新记录！\n");
        return;
    }

    printf("请输入学生信息：\n");
    printf("学号：");
    scanf("%s", students[num_students].id);

    // 检查学号是否唯一
    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[num_students].id, students[i].id) == 0) {
            printf("学号已存在，无法录入新记录！\n");
            return;
        }
    }

    printf("姓名：");
    scanf("%s", students[num_students].name);

    for (int i = 0; i < MAX_COURSE_NUM; i++) {
        printf("请输入%s成绩：", i == 0 ? "语文" : (i == 1 ? "英语" : "数学"));
        scanf("%d", &students[num_students].score[i]);
    }

    num_students++;
}

void delete_record() {
    char id[MAX_ID_LEN];
    int found = 0;

    printf("请输入要删除的学生学号：");
    scanf("%s", id);

    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[i].id, id) == 0) {
            found = 1;
            for (int j = i; j < num_students - 1; j++) {
                students[j] = students[j + 1];
            }
            num_students--;
            printf("删除成功！\n");
            break;
        }
    }

    if (!found) {
        printf("未找到该学生记录！\n");
    }
}

void query_score() {
    char id[MAX_ID_LEN];
    int found = 0;

    printf("请输入要查询的学生学号：");
    scanf("%s", id);

    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[i].id, id) == 0) {
            found = 1;
            printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
            break;
        }
    }

    if (!found) {
        printf("未找到该学生记录！\n");
    }
}

void modify_score() {
    char id[MAX_ID_LEN];
    int found = 0;
    int password;

    printf("请输入要修改成绩的学生学号：");
    scanf("%s", id);

    for (int i = 0; i < num_students; i++) {
        if (strcmp(students[i].id, id) == 0) {
            found = 1;
            password = verify_password();
            if (password) {
                printf("请输入新的成绩：\n");
                for (int j = 0; j < MAX_COURSE_NUM; j++) {
                    printf("%s：", j == 0 ? "语文" : (j == 1 ? "英语" : "数学"));
                    scanf("%d", &students[i].score[j]);
                }
                printf("成绩修改成功！\n");
            } else {
                printf("密码错误，无法修改成绩！\n");
            }
            break;
        }
    }

    if (!found) {
        printf("未找到该学生记录！\n");
    }
}

int verify_password() {
    int password;

    printf("请输入密码：");
    scanf("%d", &password);

    return password == 123456;
}

void sort_score() {
    int choice;

    printf("请选择排序方式：\n");
    printf("1、按语文成绩排序\n");
    printf("2、按英语成绩排序\n");
    printf("3、按数学成绩排序\n");
    printf("4、按平均分排序\n");
    scanf("%d", &choice);

    switch (choice) {
        case 1:
            for (int i = 0; i < num_students - 1; i++) {
                for (int j = 0; j < num_students - 1 - i; j++) {
                    if (students[j].score[0] < students[j + 1].score[0]) {
                        Student temp = students[j];
                        students[j] = students[j + 1];
                        students[j + 1] = temp;
                    }
                }
            }
            printf("按语文成绩排序结果：\n");
            for (int i = 0; i < num_students; i++) {
                printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
            }
            break;
        case 2:
            for (int i = 0; i < num_students - 1; i++) {
                for (int j = 0; j < num_students - 1 - i; j++) {
                    if (students[j].score[1] < students[j + 1].score[1]) {
                        Student temp = students[j];
                        students[j] = students[j + 1];
                        students[j + 1] = temp;
                    }
                }
            }
            printf("按英语成绩排序结果：\n");
            for (int i = 0; i < num_students; i++) {
                printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
            }
            break;
        case 3:
            for (int i = 0; i < num_students - 1; i++) {
                for (int j = 0; j < num_students - 1 - i; j++) {
                    if (students[j].score[2] < students[j + 1].score[2]) {
                        Student temp = students[j];
                        students[j] = students[j + 1];
                        students[j + 1] = temp;
                    }
                }
            }
            printf("按数学成绩排序结果：\n");
            for (int i = 0; i < num_students; i++) {
                printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
            }
            break;
        case 4:
            for (int i = 0; i < num_students - 1; i++) {
                for (int j = 0; j < num_students - 1 - i; j++) {
                    if ((students[j].score[0] + students[j].score[1] + students[j].score[2]) / 3.0 < (students[j + 1].score[0] + students[j + 1].score[1] + students[j + 1].score[2]) / 3.0) {
                        Student temp = students[j];
                        students[j] = students[j + 1];
                        students[j + 1] = temp;
                    }
                }
            }
            printf("按平均分排序结果：\n");
            for (int i = 0; i < num_students; i++) {
                printf("%s %s %d %d %d\n", students[i].id, students[i].name, students[i].score[0], students[i].score[1], students[i].score[2]);
            }
            break;
        default:
            printf("无效的排序方式！\n");
    }
}

void save_data() {
    FILE *fp;
    char filename[100];

    printf("请输入数据文件名：");
    scanf("%s", filename);

    fp = fopen(filename, "wb");
    if (fp == NULL) {
        printf("打开文件失败！\n");
        return;
    }

    fwrite(&num_students, sizeof(num_students), 1, fp);
    fwrite(students, sizeof(Student), num_students, fp);

    printf("数据保存成功！\n");

    fclose(fp);
}

void statistics() {
    int max_scores[MAX_COURSE_NUM] = {0};
    int total_scores[MAX_COURSE_NUM] = {0};
    int num_students_above_avg[MAX_COURSE_NUM] = {0};
    double avg_scores[MAX_COURSE_NUM];

    // 计算每门课程成绩最高的学生的基本信息
    for (int i = 0; i < MAX_COURSE_NUM; i++) {
        for (int j = 0; j < num_students; j++) {
            if (students[j].score[i] > students[max_scores[i]].score[i]) {
                max_scores[i] = j;
            }
        }
        printf("%s成绩最高的学生信息：\n", i == 0 ? "语文" : (i ==