C语言，有些模块没学过

Question

你好，我现在要用C语言做一个学生考试系统。
首先，要做一个学生和教师的登录验证，登录之后会显示学生和教师的基本信息。
当学生登录后，学生可以选择考试和查询成绩。若学生选择考试，则显示可以考试的科目与时间，当学生选择其中一个科目并进入考试，则显示考试的题目，学生需要输入自己的答案，到截止时间，考试结束，学生的选择题答案，与预先提供的标答，自动匹配批改，每道题2分。
教师登录后，可以选择管理学生信息，进行修改，包括添加、删除。也可以选择批改试卷，对学生的答案进行打分，分值为0-10分。
最后对学生成绩进行汇总，并按从高到低进行排序。

Answer 1

这样？

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

struct student {
    char name[20];
    char password[20];
    int score;
};

struct teacher {
    char name[20];
    char password[20];
};

int student_login(struct student *students, int n)
{
    char name[20];
    char password[20];

    printf("请输入用户名：");
    scanf("%s", name);
    printf("请输入密码：");
    scanf("%s", password);

    for (int i = 0; i < n; i++) {
        if (strcmp(students[i].name, name) == 0 && strcmp(students[i].password, password) == 0) {
            printf("登录成功！\n");
            printf("欢迎您，%s！\n", students[i].name);
            return i;
        }
    }

    printf("用户名或密码错误！\n");
    return -1;
}

int teacher_login(struct teacher *teachers, int n)
{
    char name[20];
    char password[20];

    printf("请输入用户名：");
    scanf("%s", name);
    printf("请输入密码：");
    scanf("%s", password);

    for (int i = 0; i < n; i++) {
        if (strcmp(teachers[i].name, name) == 0 && strcmp(teachers[i].password, password) == 0) {
            printf("登录成功！\n");
            printf("欢迎您，%s！\n", teachers[i].name);
            return i;
        }
    }

    printf("用户名或密码错误！\n");
    return -1;
}

void add_student(struct student *students, int n)
{
    printf("请输入学生姓名：");
    scanf("%s", students[n].name);
    printf("请输入学生密码：");
    scanf("%s", students[n].password);
    students[n].score = 0;

    printf("添加成功！\n");
}

void delete_student(struct student *students, int n)
{
    char name[20];

    printf("请输入要删除的学生姓名：");
    scanf("%s", name);

    for (int i = 0; i < n; i++) {
        if (strcmp(students[i].name, name) == 0) {
            for (int j = i; j < n - 1; j++) {
                students[j] = students[j + 1];
            }

            printf("删除成功！\n");
            return;
        }
    }

    printf("未找到该学生！\n");
}

void print_student_scores(struct student *students, int n)
{
    printf("%-10s%-10s\n", "姓名", "成绩");
    for (int i = 0; i < n; i++) {
        printf("%-10s%-10d\n", students[i].name, students[i].score);
    }
}

void modify_student_score(struct student *students, int n)
{
    char name[20];
    int score;

    printf("请输入要修改成绩的学生姓名：");
    scanf("%s", name);

    for (int i = 0; i < n; i++) {
        if (strcmp(students[i].name, name) == 0) {
            printf("请输入新的成绩：");
            scanf("%d", &score);
            students[i].score = score;
            printf("修改成功！\n");
            return;
        }
    }

    printf("未找到该学生！\n");
}

void exam(struct student *students, int student_index)
{
    char *subjects[] = {"数学", "语文", "英语", "物理"};
    char *questions[] = {
        "1 + 1 = ?\nA. 1\nB. 2\nC. 3\nD. 4\n",
        "我国的首都是？\nA. 北京\nB. 上海\nC. 广州\nD. 深圳\n",
        "What's your name?\nA. Tom\nB. Mike\nC. Jack\nD. None of the above\n",
        "牛顿第二定律的公式为？\nA. F = ma\nB. E = mc2\nC. F = G(m1m2)/r^2\nD. P = F/A\n"
    };
    char *answers[] = {"B", "A", "D", "A"};

    int choice;

    printf("请选择考试科目：\n");
    for (int i = 0; i < 4; i++) {
        printf("%d. %s\n", i + 1, subjects[i]);
    }

    scanf("%d", &choice);
    choice--;

    printf("开始考试！\n");
    printf("--------------------\n");
    
    for (int i = 0; i < 4; i++) {
        printf("第%d题：\n%s", i + 1, questions[i]);
        char answer[10];
        scanf("%s", answer);
        
        if (strcmp(answer, answers[i]) == 0) {
            printf("你的答案是：%s，恭喜你，回答正确！\n", answer);
            students[student_index].score += 2;
        } else {
            printf("你的答案是：%s，很遗憾，回答错误！\n", answer);
        }
    }

    printf("考试结束！\n");
    printf("--------------------\n");
}
void init(struct student *students, int *student_count, struct teacher *teachers, int *teacher_count) {
    // 添加学生信息
    strcpy(students[0].name, "小明");
    strcpy(students[0].password, "123456");
    students[0].score = 0;

    strcpy(students[1].name, "小红");
    strcpy(students[1].password, "111111");
    students[1].score = 0;

    *student_count = 2;

    // 添加教师信息
    strcpy(teachers[0].name, "张老师");
    strcpy(teachers[0].password, "123456");

    *teacher_count = 1;
}

int main()
{
    struct student students[100];
    int student_count = 0;

    struct teacher teachers[100];
    int teacher_count = 0;

    int student_index = -1;
    int teacher_index = -1;

    int choice;
    

    init(students, &student_count, teachers, &teacher_count);
    while (1) {
        printf("请选择登录身份：\n");
        printf("1. 学生\n");
        printf("2. 教师\n");
        printf("3. 退出程序\n");

        scanf("%d", &choice);

        if (choice == 1) {
            student_index = student_login(students, student_count);
            if (student_index != -1) {
                while (1) {
                    printf("请选择操作：\n");
                    printf("1. 开始考试\n");
                    printf("2. 退出登录\n");
                    scanf("%d", &choice);

                    if (choice == 1) {
                        exam(students, student_index);
                    } else if (choice == 2) {
                        student_index = -1;
                        break;
                    } else {
                        printf("输入有误，请重新输入！\n");
                    }
                }
            }
        } else if (choice == 2) {
            teacher_index = teacher_login(teachers, teacher_count);
            if (teacher_index != -1) {
                while (1) {
                    printf("请选择操作：\n");
                    printf("1. 添加学生\n");
                    printf("2. 删除学生\n");
                    printf("3. 查看成绩\n");
                    printf("4. 修改成绩\n");
                    printf("5. 退出登录\n");
                    scanf("%d", &choice);

                    if (choice == 1) {
                        add_student(students, student_count);
                        student_count++;
                    } else if (choice == 2) {
                        delete_student(students, student_count);
                        student_count--;
                    } else if (choice == 3) {
                        print_student_scores(students, student_count);
                    } else if (choice == 4) {
                        modify_student_score(students, student_count);
                    } else if (choice == 5) {
                        teacher_index = -1;
                        break;
                    } else {
                        printf("输入有误，请重新输入！\n");
                    }
                }
            }
        } else if (choice == 3) {
            break;
        } else {
            printf("输入有误，请重新输入！\n");
        }
    }

    printf("程序已退出！\n");

    return 0;
}