用c语言

好的，下面是一个简单的学生成绩管理系统的 C 语言代码：

#include <stdio.h>

#define MAX_NUM_STUDENTS 10
#define NUM_COURSES 3

typedef struct {
    int id;
    char name[20];
    int scores[NUM_COURSES];
    int total_score;
    float avg_score;
} Student;

void input_student(Student* student) {
    printf("请输入学生的学号、姓名和成绩:\n");
    scanf("%d %s %d %d %d", &student->id, student->name, &student->scores[0], &student->scores[1], &student->scores[2]);
    student->total_score = student->scores[0] + student->scores[1] + student->scores[2];
    student->avg_score = (float) student->total_score / NUM_COURSES;
}

void print_student(const Student* student) {
    printf("%d\t%s\t%d\t%d\t%d\t%.2f\n", student->id, student->name, student->scores[0], student->scores[1], student->scores[2], student->avg_score);
}

void print_students(const Student* students, int num_students) {
    printf("学号\t姓名\t课程1\t课程2\t课程3\t平均分\n");
    for (int i = 0; i < num_students; i++) {
        print_student(&students[i]);
    }
}

void update_student(Student* student) {
    printf("请输入学生的新成绩:\n");
    scanf("%d %d %d", &student->scores[0], &student->scores[1], &student->scores[2]);
    student->total_score = student->scores[0] + student->scores[1] + student->scores[2];
    student->avg_score = (float) student->total_score / NUM_COURSES;
}

void sort_students(Student* students, int num_students) {
    for (int i = 0; i < num_students - 1; i++) {
        for (int j = i + 1; j < num_students; j++) {
            if (students[j].total_score > students[i].total_score) {
                Student temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }
}

void find_student(const Student* students, int num_students) {
    int choice;
    printf("请输入查询方式：1.按学号查询；2.按姓名查询\n");
    scanf("%d", &choice);
    if (choice == 1) {
        int id;
        printf("请输入学号:\n");
        scanf("%d", &id);
        for (int i = 0; i < num_students; i++) {
            if (students[i].id == id) {
                print_student(&students[i]);
                return;
            }
        }
        printf("找不到该学生\n");
    } else if (choice == 2) {
        char name[20];
        printf("请输入姓名:\n");
        scanf("%s", name);
        for (int i = 0; i < num_students; i++) {
            if (strcmp(students[i].name, name) == 0) {
                print_student(&students[i]);
                return;
            }
        }
        printf("找不到该学生\n");
    } else {
        printf("无效的输入\n");
    }
}

void calculate_statistics(const Student* students, int num_students) {
    float avg_scores[NUM_COURSES] = {0};
    float avg_total_score = 0;
    for (int i = 0; i < num_students; i++) {
        for (int j = 0; j < NUM_COURSES; j++) {
            avg_scores[j] += students[i].scores[j];
        }
        avg_total_score += students[i].total_score;
    }
    for (int i = 0; i < NUM_COURSES; i++) {
        avg_scores[i] /= num_students;
        printf("课程%d平均成绩：%.2f\n", i + 1, avg_scores[i]);
    }
    avg_total_score /= num_students;
    printf("学生总平均成绩：%.2f\n", avg_total_score);
}

int main() {
    Student students[MAX_NUM_STUDENTS];
    int num_students;
    printf("请输入学生人数:\n");
    scanf("%d", &num_students);
    if (num_students > MAX_NUM_STUDENTS) {
        printf("人数超过最大限制\n");
        return 1;
    }
    for (int i = 0; i < num_students; i++) {
        input_student(&students[i]);
    }
    printf("-----学生信息-----\n");
    print_students(students, num_students);
    printf("-----按总分排序-----\n");
    sort_students(students, num_students);
    print_students(students, num_students);
    printf("-----查询学生信息-----\n");
    find_student(students, num_students);
    printf("-----修改学生信息-----\n");
    int id;
    printf("请输入要修改的学生学号:\n");
    scanf("%d", &id);
    for (int i = 0; i < num_students; i++) {
        if (students[i].id == id) {
            update_student(&students[i]);
            printf("修改成功\n");
            break;
        }
    }
    printf("-----学生成绩统计-----\n");
    calculate_statistics(students, num_students);
    return 0;
}

这个程序实现了你提供的所有功能，包括输入学生信息、排序、查询、修改、统计等。你可以根据需要进行修改和扩展。