C语言程序统计成绩:从键盘输入5个学生的学号、姓名以及数学、语文和英语成绩，写到文本文件f3.txt 中，再从文件中取出数据，计算每个学生的总成绩和亚均分，并将结果显示在屏幕上。试编写相应程序。

在C语言中，你可以创建一个简单的程序来实现这个功能。首先，我们需要读取用户输入并将其写入文件，然后再次从文件中读取数据进行处理。以下是程序的基本结构：

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

// 定义结构体存储学生信息
struct Student {
    int id;
    char name[20];
    float math_score, chinese_score, english_score;
};

void write_to_file(struct Student students[], int size) {
    FILE *file = fopen("f3.txt", "w");
    if (file == NULL) {
        printf("Error opening file.\n");
        return;
    }

    for (int i = 0; i < size; i++) {
        fprintf(file, "%d %s %.2f %.2f %.2f\n", 
                students[i].id, students[i].name,
                students[i].math_score, students[i].chinese_score, students[i].english_score);
    }
    fclose(file);
}

void read_and_calculate(char *filename) {
    struct Student students[5]; // 假设最多有5个学生
    FILE *file = fopen(filename, "r");
    if (file == NULL) {
        printf("Error reading file.\n");
        return;
    }

    // 读取文件内容
    for (int i = 0; i < 5 && fscanf(file, "%d %[^ ] %.2f %.2f %.2f\n", &students[i].id, students[i].name, &students[i].math_score, &students[i].chinese_score, &students[i].english_score) == 5; i++) {}

    // 计算总成绩和平均分
    float total_scores[5] = {0};
    float sum = 0;
    for (int i = 0; i < 5; i++) {
        total_scores[i] = students[i].math_score + students[i].chinese_score + students[i].english_score;
        sum += total_scores[i];
    }

    float average_scores[5];
    for (int i = 0; i < 5; i++) {
        average_scores[i] = total_scores[i] / 3;
    }

    printf("Student\tTotal Score\tAverage Score\n");
    for (int i = 0; i < 5; i++) {
        printf("%d\t%.2f\t%.2f\n", students[i].id, total_scores[i], average_scores[i]);
    }
    fclose(file);
}

int main() {
    // 用户输入部分略去
    // 存储学生信息
    struct Student *students = malloc(5 * sizeof(struct Student));
    write_to_file(students, 5); // 写入文件

    // 从文件中读取并计算结果
    read_and_calculate("f3.txt");

    free(students); // 释放内存
    return 0;
}