给我个c语言代码，要求对一个班级学生成绩的管理，不仅能创建文件、输入班级成绩、保存文件，还能让一个班级成绩文件复制到另一个文件内容，并且能够查询成绩、修改成绩、显示所有的学生成绩。

好的，以下是一个简单的C语言代码，可以对班级学生成绩进行管理：

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

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

// 创建文件
void create_file(char *filename) {
    FILE *fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("Failed to create file!\n");
        exit(1);
    }
    fclose(fp);
    printf("File created successfully!\n");
}

// 输入班级成绩
void input_score(char *filename) {
    FILE *fp = fopen(filename, "a");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    Student student;
    printf("Please enter student information (name/id/score):\n");
    scanf("%s %d %f", student.name, &student.id, &student.score);
    fprintf(fp, "%s %d %.2f\n", student.name, student.id, student.score);
    fclose(fp);
    printf("Input student score successfully!\n");
}

// 保存文件
void save_file(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    char new_filename[30];
    printf("Please enter the new file name: ");
    scanf("%s", new_filename);
    FILE *new_fp = fopen(new_filename, "w");
    if (new_fp == NULL) {
        printf("Failed to create file!\n");
        exit(1);
    }
    char buffer[50];
    while (fgets(buffer, 50, fp) != NULL) {
        fputs(buffer, new_fp);
    }
    fclose(fp);
    fclose(new_fp);
    printf("File saved successfully!\n");
}

// 复制文件
void copy_file(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    char new_filename[30];
    printf("Please enter the new file name: ");
    scanf("%s", new_filename);
    FILE *new_fp = fopen(new_filename, "w");
    if (new_fp == NULL) {
        printf("Failed to create file!\n");
        exit(1);
    }
    char buffer[50];
    while (fgets(buffer, 50, fp) != NULL) {
        fputs(buffer, new_fp);
    }
    fclose(fp);
    fclose(new_fp);
    printf("File copied successfully!\n");
}

// 查询成绩
void query_score(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    int id;
    printf("Please enter the student id: ");
    scanf("%d", &id);
    char buffer[50];
    int found = 0;
    while (fgets(buffer, 50, fp) != NULL) {
        Student student;
        sscanf(buffer, "%s %d %f", student.name, &student.id, &student.score);
        if (id == student.id) {
            printf("Name: %s, ID: %d, Score: %.2f\n", student.name, student.id, student.score);
            found = 1;
            break;
        }
    }
    if (!found) {
        printf("Student not found!\n");
    }
    fclose(fp);
}

// 修改成绩
void modify_score(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    int id;
    printf("Please enter the student id: ");
    scanf("%d", &id);
    char buffer[50];
    int found = 0;
    FILE *new_fp = fopen("temp.txt", "w");
    if (new_fp == NULL) {
        printf("Failed to create file!\n");
        exit(1);
    }
    while (fgets(buffer, 50, fp) != NULL) {
        Student student;
        sscanf(buffer, "%s %d %f", student.name, &student.id, &student.score);
        if (id == student.id) {
            printf("Please enter the new score: ");
            scanf("%f", &student.score);
            fprintf(new_fp, "%s %d %.2f\n", student.name, student.id, student.score);
            found = 1;
        } else {
            fprintf(new_fp, "%s %d %.2f\n", student.name, student.id, student.score);
        }
    }
    fclose(fp);
    fclose(new_fp);
    remove(filename);
    rename("temp.txt", filename);
    if (found) {
        printf("Score modified successfully!\n");
    } else {
        printf("Student not found!\n");
    }
}

// 显示所有学生成绩
void display_score(char *filename) {
    FILE *fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file!\n");
        exit(1);
    }
    char buffer[50];
    while (fgets(buffer, 50, fp) != NULL) {
        Student student;
        sscanf(buffer, "%s %d %f", student.name, &student.id, &student.score);
        printf("Name: %s, ID: %d, Score: %.2f\n", student.name, student.id, student.score);
    }
    fclose(fp);
}

int main() {
    char filename[30];
    printf("Please enter the file name: ");
    scanf("%s", filename);
    create_file(filename);
    int choice;
    do {
        printf("\nMenu:\n");
        printf("1. Input score\n");
        printf("2. Save file\n");
        printf("3. Copy file\n");
        printf("4. Query score\n");
        printf("5. Modify score\n");
        printf("6. Display score\n");
        printf("0. Exit\n");
        printf("Please enter your choice: ");
        scanf("%d", &choice);
        switch (choice) {
            case 1:
                input_score(filename);
                break;
            case 2:
                save_file(filename);
                break;
            case 3:
                copy_file(filename);
                break;
            case 4:
                query_score(filename);
                break;
            case 5:
                modify_score(filename);
                break;
            case 6:
                display_score(filename);
                break;
            case 0:
                printf("Goodbye!\n");
                break;
            default:
                printf("Invalid choice!\n");
                break;
        }
    } while (choice != 0);
    return 0;
}

这个程序可以完成你所要求的所有功能，你可以根据需要进行修改和完善。