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，数学，语言。该系统实现对班级成绩的录入、显示,统计等操作的管理。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、 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 （该题目用或数组完成）

好的，这是一个较为复杂的问题，需要比较长的一段代码来实现。请注意，以下代码仅供参考。

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

#define MAX_STUDENT 100

struct Student {
    int id;
    char name[20];
    int score[3];  // 0: Chinese, 1: Math, 2: English
};

struct Student students[MAX_STUDENT];
int student_count = 0;

int find_student(int id) {
    for (int i = 0; i < student_count; i++) {
        if (students[i].id == id) {
            return i;
        }
    }
    return -1;
}

void import_data() {
    printf("Please enter the number of students: ");
    scanf("%d", &student_count);
    for (int i = 0; i < student_count; i++) {
        printf("Student #%d\n", i + 1);
        printf("ID: ");
        scanf("%d", &students[i].id);
        if (find_student(students[i].id) != -1) {
            printf("Error: duplicate student ID\n");
            i--;
            continue;
        }
        printf("Name: ");
        scanf("%s", students[i].name);
        printf("Chinese score: ");
        scanf("%d", &students[i].score[0]);
        printf("Math score: ");
        scanf("%d", &students[i].score[1]);
        printf("English score: ");
        scanf("%d", &students[i].score[2]);
    }
}

void show_data() {
    printf("%-10s%-20s%-10s%-10s%-10s\n", "ID", "Name", "Chinese", "Math", "English");
    for (int i = 0; i < student_count; i++) {
        printf("%-10d%-20s%-10d%-10d%-10d\n", students[i].id, students[i].name,
            students[i].score[0], students[i].score[1], students[i].score[2]);
    }
}

void add_student() {
    printf("Please enter the information of the new student:\n");
    printf("ID: ");
    int id;
    scanf("%d", &id);
    if (find_student(id) != -1) {
        printf("Error: duplicate student ID\n");
        return;
    }
    strcpy(students[student_count].name, "");
    students[student_count].id = id;
    printf("Name: ");
    scanf("%s", students[student_count].name);
    printf("Chinese score: ");
    scanf("%d", &students[student_count].score[0]);
    printf("Math score: ");
    scanf("%d", &students[student_count].score[1]);
    printf("English score: ");
    scanf("%d", &students[student_count].score[2]);
    student_count++;
}

void print_highest(int subject) {
    int highest_score = -1;
    int highest_index = -1;
    for (int i = 0; i < student_count; i++) {
        if (students[i].score[subject] > highest_score) {
            highest_score = students[i].score[subject];
            highest_index = i;
        }
    }
    printf("%-10s%-20s%-10d\n", "ID", "Name", highest_score);
    printf("%-10d%-20s%-10d\n", students[highest_index].id, students[highest_index].name,
        students[highest_index].score[subject]);
}

void print_average(int subject) {
    int sum = 0;
    for (int i = 0; i < student_count; i++) {
        sum += students[i].score[subject];
    }
    double average = (double)sum / student_count;
    printf("The average score of %s is %.2lf\n",
        subject == 0 ? "Chinese" : subject == 1 ? "Math" : "English", average);
}

void count_above_average(int subject) {
    int count = 0;
    int sum = 0;
    for (int i = 0; i < student_count; i++) {
        sum += students[i].score[subject];
    }
    double average = (double)sum / student_count;
    for (int i = 0; i < student_count; i++) {
        if (students[i].score[subject] > average) {
            count++;
        }
    }
    printf("%d students got above-average score in %s\n", count,
        subject == 0 ? "Chinese" : subject == 1 ? "Math" : "English");
}

int main() {
    char command;
    do {
        printf("System options:\n");
        printf("a. Import data and show\n");
        printf("b. Add new record\n");
        printf("c. Show statistics\n");
        printf("g. Quit\n");
        printf("Please enter your command: ");
        scanf(" %c", &command);
        switch (command) {
            case 'a':
                import_data();
                show_data();
                break;
            case 'b':
                add_student();
                show_data();
                break;
            case 'c': {
                int sub_command;
                do {
                    printf("Statistics:\n");
                    printf("1. Show the highest score of each subject\n");
                    printf("2. Show the average score of each subject\n");
                    printf("3. Count the number of students who got above-average score\n");
                    printf("Please enter your command: ");
                    scanf("%d", &sub_command);
                    switch (sub_command) {
                        case 1:
                            printf("%-10s%-20s%-10s\n", "Subject", "Name", "Score");
                            print_highest(0);
                            print_highest(1);
                            print_highest(2);
                            break;
                        case 2:
                            print_average(0);
                            print_average(1);
                            print_average(2);
                            break;
                        case 3:
                            count_above_average(0);
                            count_above_average(1);
                            count_above_average(2);
                            break;
                        default:
                            printf("Invalid command\n");
                            break;
                    }
                } while (sub_command != 1 && sub_command != 2 && sub_command != 3);
                break;
            }
            case 'g':
                printf("Goodbye!\n");
                break;
            default:
                printf("Invalid command\n");
                break;
        }
    } while (command != 'g');
    return 0;
}

这段代码使用了一个 `struct` 结构体数组来存储学生信息，其中包括学号、姓名、三门课程的成绩。菜单选项包括数据导入及显示、新记录输入、成绩统计等。具体的实现细节可以自行参考代码注释。