帮我用C语言编程，要求如下：设计编写一个传统的小型学生信息管理系统。 1、该系统可以用于管理一个班的学生信息。学生人数在50人左右。 2、该系统存放了有关学生的某些方面的信息：如学号、姓名、性别、出生日期、成绩、所在系等，具体包含的数据内容由设计者分析确定。 3、所有学生信息的数据结构及其存储结构由设计者分析确定。 4、所有学生的信息数据可以用文件形式存放。（可选项） 5、该系统具有相关的数据输入、输出、查询、修改、插入、删除、统计、排序等功能。（功能的多少设计者可根据需要自行调整，但必须具备输出、输出、查询、某一方面数据统计的基本功能。） 6、系统应具有友好的用户界面，并能够让用户通过菜单进行相应功能的选择。 7、选用适当的算法和数据结构，建立相应的程序代码。8、不使用fopen函数

好的，以下是一个简单的学生信息管理系统的C语言实现，实现了基本的数据输入、输出、查询、统计、排序等功能，数据使用结构体数组存储，没有使用fopen函数。

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

#define MAX_STUDENT_NUM 50
#define ID_LEN 10
#define NAME_LEN 20
#define GENDER_LEN 5
#define BIRTH_LEN 15
#define DEPT_LEN 20

typedef struct Student {
    char id[ID_LEN];
    char name[NAME_LEN];
    char gender[GENDER_LEN];
    char birth[BIRTH_LEN];
    float score;
    char department[DEPT_LEN];
} Student;

Student students[MAX_STUDENT_NUM];
int student_num = 0;

void add_student() {
    if (student_num >= MAX_STUDENT_NUM) {
        printf("Max student number exceeded!\n");
        return;
    }
    printf("Please input student information:\n");
    printf("ID: ");
    scanf("%s", students[student_num].id);
    printf("Name: ");
    scanf("%s", students[student_num].name);
    printf("Gender: ");
    scanf("%s", students[student_num].gender);
    printf("Birth: ");
    scanf("%s", students[student_num].birth);
    printf("Score: ");
    scanf("%f", &students[student_num].score);
    printf("Department: ");
    scanf("%s", students[student_num].department);
    student_num++;
    printf("Student added successfully!\n");
}

void print_student(Student student) {
    printf("%s\t%s\t%s\t%s\t%.2f\t%s\n", student.id, student.name, student.gender, student.birth, student.score, student.department);
}

void print_all_students() {
    printf("All students:\n");
    printf("ID\tName\tGender\tBirth\tScore\tDepartment\n");
    for (int i = 0; i < student_num; i++) {
        print_student(students[i]);
    }
}

int find_student(char id[ID_LEN]) {
    for (int i = 0; i < student_num; i++) {
        if (strcmp(students[i].id, id) == 0) {
            return i;
        }
    }
    return -1;
}

void query_student() {
    char id[ID_LEN];
    printf("Please input student ID: ");
    scanf("%s", id);
    int index = find_student(id);
    if (index == -1) {
        printf("Student not found!\n");
    } else {
        print_student(students[index]);
    }
}

void update_student() {
    char id[ID_LEN];
    printf("Please input student ID: ");
    scanf("%s", id);
    int index = find_student(id);
    if (index == -1) {
        printf("Student not found!\n");
    } else {
        printf("Please input new student information:\n");
        printf("ID: ");
        scanf("%s", students[index].id);
        printf("Name: ");
        scanf("%s", students[index].name);
        printf("Gender: ");
        scanf("%s", students[index].gender);
        printf("Birth: ");
        scanf("%s", students[index].birth);
        printf("Score: ");
        scanf("%f", &students[index].score);
        printf("Department: ");
        scanf("%s", students[index].department);
        printf("Student updated successfully!\n");
    }
}

void delete_student() {
    char id[ID_LEN];
    printf("Please input student ID: ");
    scanf("%s", id);
    int index = find_student(id);
    if (index == -1) {
        printf("Student not found!\n");
    } else {
        for (int i = index; i < student_num - 1; i++) {
            students[i] = students[i + 1];
        }
        student_num--;
        printf("Student deleted successfully!\n");
    }
}

void sort_students_by_score() {
    for (int i = 0; i < student_num - 1; i++) {
        for (int j = 0; j < student_num - i - 1; j++) {
            if (students[j].score < students[j + 1].score) {
                Student temp = students[j];
                students[j] = students[j + 1];
                students[j + 1] = temp;
            }
        }
    }
    printf("Students sorted by score!\n");
}

void count_students_by_dept() {
    char department[DEPT_LEN];
    printf("Please input department name: ");
    scanf("%s", department);
    int count = 0;
    for (int i = 0; i < student_num; i++) {
        if (strcmp(students[i].department, department) == 0) {
            count++;
        }
    }
    printf("There are %d students in department %s.\n", count, department);
}

int main() {
    int choice;
    while (1) {
        printf("Please select a function:\n");
        printf("1. Add student\n");
        printf("2. Print all students\n");
        printf("3. Query student\n");
        printf("4. Update student\n");
        printf("5. Delete student\n");
        printf("6. Sort students by score\n");
        printf("7. Count students by department\n");
        printf("8. Exit\n");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                add_student();
                break;
            case 2:
                print_all_students();
                break;
            case 3:
                query_student();
                break;
            case 4:
                update_student();
                break;
            case 5:
                delete_student();
                break;
            case 6:
                sort_students_by_score();
                break;
            case 7:
                count_students_by_dept();
                break;
            case 8:
                return 0;
            default:
                printf("Invalid choice!\n");
        }
    }
    return 0;
}

这个学生信息管理系统实现了基本的数据输入、输出、查询、修改、插入、删除、统计、排序等功能，使用了结构体数组来存储学生信息，没有使用fopen函数。用户可以通过菜单进行相应功能的选择，实现了友好的用户界面。