用c语言写一个学生成绩管理系统，分模块写，分别放到main.c文件和stusys.h头文件中

好的，我可以帮你写一个学生成绩管理系统的程序，以下是我根据你的要求所写的代码：

// stusys.h 头文件

#ifndef _STUSYS_H_
#define _STUSYS_H_

typedef struct Student {
    char name[20];
    int id;
    int score;
} Student;

void addStudent(Student *students, int *numStudents);
void delStudent(Student *students, int *numStudents);
void modifyStudent(Student *students, int numStudents);
void searchStudent(Student *students, int numStudents);
void sortStudents(Student *students, int numStudents);

#endif


// main.c 文件

#include <stdio.h>
#include <stdlib.h>
#include "stusys.h"

#define MAX_STUDENTS 100

int main()
{
    Student students[MAX_STUDENTS];
    int numStudents = 0;
    int choice;

    do {
        printf("请选择操作：\n");
        printf("1. 添加学生\n");
        printf("2. 删除学生\n");
        printf("3. 修改学生\n");
        printf("4. 查找学生\n");
        printf("5. 排序学生\n");
        printf("6. 退出程序\n");
        printf("请选择：");
        scanf("%d", &choice);

        switch (choice) {
            case 1:
                addStudent(students, &numStudents);
                break;
            case 2:
                delStudent(students, &numStudents);
                break;
            case 3:
                modifyStudent(students, numStudents);
                break;
            case 4:
                searchStudent(students, numStudents);
                break;
            case 5:
                sortStudents(students, numStudents);
                break;
            case 6:
                printf("程序已退出\n");
                break;
            default:
                printf("无效的选项，请重新选择\n");
                break;
        }

    } while (choice != 6);

    return 0;
}


// stusys.c 文件

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "stusys.h"

void addStudent(Student *students, int *numStudents)
{
    if (*numStudents == MAX_STUDENTS) {
        printf("学生数量已达到上限，无法添加\n");
        return;
    }

    Student newStudent;

    printf("请输入学生姓名：");
    scanf("%s", newStudent.name);
    printf("请输入学生学号：");
    scanf("%d", &newStudent.id);
    printf("请输入学生分数：");
    scanf("%d", &newStudent.score);

    students[*numStudents] = newStudent;
    (*numStudents)++;

    printf("添加成功\n");
}

void delStudent(Student *students, int *numStudents)
{
    int idToDelete;

    printf("请输入要删除的学生学号：");
    scanf("%d", &idToDelete);

    int indexToDelete = -1;

    for (int i = 0; i < *numStudents; i++) {
        if (students[i].id == idToDelete) {
            indexToDelete = i;
            break;
        }
    }

    if (indexToDelete == -1) {
        printf("找不到学号为 %d 的学生\n", idToDelete);
        return;
    }

    for (int i = indexToDelete; i < *numStudents - 1; i++) {
        students[i] = students[i + 1];
    }

    (*numStudents)--;

    printf("删除成功\n");
}

void modifyStudent(Student *students, int numStudents)
{
    int idToModify;

    printf("请输入要修改的学生学号：");
    scanf("%d", &idToModify);

    int indexToModify = -1;

    for (int i = 0; i < numStudents; i++) {
        if (students[i].id == idToModify) {
            indexToModify = i;
            break;
        }
    }

    if (indexToModify == -1) {
        printf("找不到学号为 %d 的学生\n", idToModify);
        return;
    }

    printf("请输入修改后的学生姓名：");
    scanf("%s", students[indexToModify].name);
    printf("请输入修改后的学生分数：");
    scanf("%d", &students[indexToModify].score);

    printf("修改成功\n");
}

void searchStudent(Student *students, int numStudents)
{
    int choice;

    printf("请选择查找方式：\n");
    printf("1. 按姓名查找\n");
    printf("2. 按学号查找\n");
    printf("请选择：");
    scanf("%d", &choice);

    switch (choice) {
        case 1:
            char nameToSearch[20];

            printf("请输入要查找的学生姓名：");
            scanf("%s", nameToSearch);

            for (int i = 0; i < numStudents; i++) {
                if (strcmp(students[i].name, nameToSearch) == 0) {
                    printf("学生姓名：%s，学号：%d，分数：%d\n", students[i].name, students[i].id, students[i].score);
                }
            }

            break;
        case 2:
            int idToSearch;

            printf("请输入要查找的学生学号：");
            scanf("%d", &idToSearch);

            for (int i = 0; i < numStudents; i++) {
                if (students[i].id == idToSearch) {
                    printf("学生姓名：%s，学号：%d，分数：%d\n", students[i].name, students[i].id, students[i].score);
                    break;
                }
            }

            break;
        default:
            printf("无效的选项，请重新选择\n");
            break;
    }
}

void sortStudents(Student *students, int numStudents)
{
    for (int i = 0; i < numStudents - 1; i++) {
        for (int j = i + 1; j < numStudents; j++) {
            if (students[i].score < students[j].score) {
                Student temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }

    printf("排序成功\n");
}

这样，你就可以把 `stusys.h` 和 `stusys.c` 文件放在同一个目录下，然后在 `main.c` 文件中包含 `stusys.h` 头文件，并调用其提供的函数来管理学生信息了。注意，以上代码只是一个示例，具体实现根据你的需求可能需要进行修改。