设计一个成绩处理程序，处理m个学生、n门课程（至少5门课）的成绩。用结构体来存储数据，结构体的成员包括：学号、姓名、性别、n门课成绩。先输入这些学号、姓名、性别、n门课成绩，然后显示功能菜单，调用功能函数，完成包括以下功能： （1）求每个学生n门课程成绩的总分、平均分 （2）求每门课程成绩的平均分 （3）按输入成绩的顺序，显示指定第i个人的总分和平均分 （4）按输入成绩的顺序，显示指定第i个人的第j门课成绩，并显示改成绩是高 于课程平均分还是低于课程平均分。 （5）求每个学生按平均分的排名 （6）数字0，则退出程序（结束运行）

好的，这是一个比较完整的程序，我会尽力为您解答。以下是程序代码，您可以参考学习：

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

#define MAX_NAME_LENGTH 20
#define MAX_SUBJECT_NUM 5
#define MAX_STUDENT_NUM 100

typedef struct {
    char id[20];
    char name[MAX_NAME_LENGTH];
    char gender[5];
    float score[MAX_SUBJECT_NUM];
    float sum_score;
    float avg_score;
    int rank;
} student;

student students[MAX_STUDENT_NUM];
int student_num;
int subject_num;

void input_students() {
    printf("请输入学生数：");
    scanf("%d", &student_num);
    printf("请输入课程数：");
    scanf("%d", &subject_num);

    for (int i = 0; i < student_num; i++) {
        student *s = &students[i];
        printf("请输入第%d个学生的信息：\n", i + 1);
        printf("学号：");
        scanf("%s", s->id);
        printf("姓名：");
        scanf("%s", s->name);
        printf("性别：");
        scanf("%s", s->gender);
        printf("成绩：");
        for (int j = 0; j < subject_num; j++) {
            scanf("%f", &s->score[j]);
            s->sum_score += s->score[j];
        }
        s->avg_score = s->sum_score / subject_num;
    }
}

void show_menu() {
    printf("\n请选择要执行的操作：\n");
    printf("1、求每个学生n门课程成绩的总分、平均分\n");
    printf("2、求每门课程成绩的平均分\n");
    printf("3、按输入成绩的顺序，显示指定第i个人的总分和平均分\n");
    printf("4、按输入成绩的顺序，显示指定第i个人的第j门课成绩，并显示该成绩是高于课程平均分还是低于课程平均分\n");
    printf("5、求每个学生按平均分的排名\n");
    printf("0、退出程序\n");
}

void show_student_score() {
    printf("学号\t\t姓名\t\t总分\t\t平均分\n");
    for (int i = 0; i < student_num; i++) {
        student *s = &students[i];
        printf("%s\t\t%s\t\t%.2f\t\t%.2f\n", s->id, s->name, s->sum_score, s->avg_score);
    }
}

void show_subject_score() {
    printf("课程\t\t平均分\n");
    for (int i = 0; i < subject_num; i++) {
        float sum_score = 0;
        for (int j = 0; j < student_num; j++) {
            student *s = &students[j];
            sum_score += s->score[i];
        }
        float avg_score = sum_score / student_num;
        printf("课程%d\t\t%.2f\n", i + 1, avg_score);
    }
}

void show_one_student_score() {
    int i;
    printf("请输入要查询的学生序号：");
    scanf("%d", &i);
    if (i > 0 && i <= student_num) {
        student *s = &students[i - 1];
        printf("学号：%s\n", s->id);
        printf("姓名：%s\n", s->name);
        printf("总分：%.2f\n", s->sum_score);
        printf("平均分：%.2f\n", s->avg_score);
    } else {
        printf("查询失败，学生序号不存在！\n");
    }
}

void show_one_student_subject_score() {
    int i, j;
    printf("请输入要查询的学生序号和课程序号，用空格隔开：");
    scanf("%d %d", &i, &j);
    if (i > 0 && i <= student_num && j > 0 && j <= subject_num) {
        student *s = &students[i - 1];
        float score = s->score[j - 1];
        float avg_score = 0;
        for (int k = 0; k < student_num; k++) {
            student *t = &students[k];
            avg_score += t->score[j - 1];
        }
        avg_score /= student_num;
        printf("学号：%s\n", s->id);
        printf("姓名：%s\n", s->name);
        printf("成绩：%.2f\n", score);
        if (score > avg_score) {
            printf("该成绩高于课程平均分！\n");
        } else if (score < avg_score) {
            printf("该成绩低于课程平均分！\n");
        } else {
            printf("该成绩等于课程平均分！\n");
        }
    } else {
        printf("查询失败，学生序号或课程序号不存在！\n");
    }
}

void sort_students() {
    for (int i = 0; i < student_num; i++) {
        int r = 1;
        student *s = &students[i];
        for (int j = 0; j < student_num; j++) {
            student *t = &students[j];
            if (s->avg_score < t->avg_score) {
                r++;
            }
        }
        s->rank = r;
    }
}

void show_student_rank() {
    printf("学号\t\t姓名\t\t平均分\t\t排名\n");
    sort_students();
    for (int i = 0; i < student_num; i++) {
        student *s = &students[i];
        printf("%s\t\t%s\t\t%.2f\t\t%d\n", s->id, s->name, s->avg_score, s->rank);
    }
}

void run() {
    int choice = -1;
    while (choice != 0) {
        show_menu();
        printf("请选择要执行的操作：");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                show_student_score();
                break;
            case 2:
                show_subject_score();
                break;
            case 3:
                show_one_student_score();
                break;
            case 4:
                show_one_student_subject_score();
                break;
            case 5:
                show_student_rank();
                break;
            case 0:
                printf("程序已退出！\n");
                break;
            default:
                printf("无效的选择，请重新输入！\n");
                break;
        }
    }
}

int main() {
    input_students();
    run();
    return 0;
}

这个程序比较长，但是它实现了题目中要求的所有功能。如果有任何不理解的地方，可以随时问我。