请帮我用C语言编写一个学生成绩统计管理的代码

好的，以下是一个简单的学生成绩统计管理程序的C语言代码示例：

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

#define MAX_STUDENT_NUM 10
#define MAX_SUBJECT_NUM 5

typedef struct {
    char name[20];
    float score[MAX_SUBJECT_NUM];
    float average_score;
} Student;

float calculate_average_score(float scores[], int count) {
    float sum = 0;
    for (int i = 0; i < count; i++) {
        sum += scores[i];
    }
    return sum / count;
}

void calculate_all_average_scores(Student students[], int student_count) {
    for (int i = 0; i < student_count; i++) {
        students[i].average_score = calculate_average_score(students[i].score, MAX_SUBJECT_NUM);
    }
}

void find_highest_score(Student students[], int student_count, char *subject_name) {
    float max_score = -1;
    int max_score_student_index = -1;
    for (int i = 0; i < student_count; i++) {
        for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
            if (strcmp(subject_name, "all") != 0 && strcmp(subject_name, "All") != 0 && strcmp(subject_name, "ALL") != 0 && strcmp(subject_name, "全部") != 0) {
                if (strcmp(subject_name, "语文") == 0 && j != 0) {
                    continue;
                } else if (strcmp(subject_name, "数学") == 0 && j != 1) {
                    continue;
                } else if (strcmp(subject_name, "英语") == 0 && j != 2) {
                    continue;
                } else if (strcmp(subject_name, "物理") == 0 && j != 3) {
                    continue;
                } else if (strcmp(subject_name, "化学") == 0 && j != 4) {
                    continue;
                }
            }
            if (students[i].score[j] > max_score) {
                max_score = students[i].score[j];
                max_score_student_index = i;
            }
        }
    }
    if (max_score_student_index != -1) {
        printf("最高分数为%.2f，对应学生是%s，对应科目是%s\n", max_score, students[max_score_student_index].name, subject_name);
    }
}

float calculate_average_score_variance(Student students[], int student_count) {
    float sum = 0;
    float average_scores[MAX_STUDENT_NUM];
    for (int i = 0; i < student_count; i++) {
        average_scores[i] = students[i].average_score;
        sum += average_scores[i];
    }
    float average = sum / student_count;
    float variance = 0;
    for (int i = 0; i < student_count; i++) {
        variance += pow(average_scores[i] - average, 2);
    }
    return variance / student_count;
}

int main() {
    Student students[MAX_STUDENT_NUM];
    int student_count = 0;
    char subject_name[10];

    printf("请输入学生个数（不超过%d个）：", MAX_STUDENT_NUM);
    scanf("%d", &student_count);
    for (int i = 0; i < student_count; i++) {
        printf("请输入第%d个学生的名字：", i + 1);
        scanf("%s", students[i].name);
        for (int j = 0; j < MAX_SUBJECT_NUM; j++) {
            printf("请输入%s的%s成绩：", students[i].name, j == 0 ? "语文" : (j == 1 ? "数学" : (j == 2 ? "英语" : (j == 3 ? "物理" : "化学"))));
            scanf("%f", &students[i].score[j]);
        }
    }

    calculate_all_average_scores(students, student_count);
    for (int i = 0; i < student_count; i++) {
        printf("%s的平均分为%.2f\n", students[i].name, students[i].average_score);
    }

    printf("请输入要查询的科目名（输入“全部”或“all”或“All”或“ALL”查询所有科目）：");
    scanf("%s", subject_name);
    find_highest_score(students, student_count, subject_name);

    float variance = calculate_average_score_variance(students, student_count);
    printf("平均分方差为%.2f\n", variance);

    return 0;
}

该程序实现了以下功能：

1. 输入学生个数和每个学生的成绩，并计算每个学生的平均分；
2. 输出每个学生的平均分；
3. 输入要查询的科目名，输出该科目中所有学生的最高分数对应的学生和课程；
4. 计算所有学生的平均分方差，并输出结果。

请注意，该程序中的科目名只支持输入“语文”、“数学”、“英语”、“物理”和“化学”，如果需要增加或修改科目名，请修改find_highest_score函数中的代码。