14.文件score.txt保存了学生的平时成绩和期末成绩，内容如下: 学号,平时成绩,期末成绩 9999180101,77,88 9999180102,91,85 9999180103,87,96 9999180104,70,68 9999180105,86,72 编写程序读取所有成绩，计算总评成绩（四舍五入到整数），其中总评成绩=平时成绩40%+期末成绩60%。最后按总评成绩降序排列后保存至一个新的文件内，文件内容应该如下：学号,平时成绩,期末成绩,总评成绩 9999180103,87,96,92 9999180102,91,85,87 9999180101,77,88,84 9999180105,86,72,78 9999180104,70,68,69

下面是一个实现上述功能的C语言代码：

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

#define MAX_STUDENTS 100

// 定义学生结构体
typedef struct {
    char id[11];    // 学号
    int pscore;     // 平时成绩
    int fscore;     // 期末成绩
    int tscore;     // 总评成绩
} Student;

// 读取文件中的学生信息
int read_students(Student *students, const char *filename) {
    FILE *fp;
    int count = 0;
    fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file %s", filename);
        exit(1);
    }
    // 逐行读取学生信息
    while (fscanf(fp, "%[^,],%d,%d\n", students[count].id, &students[count].pscore, &students[count].fscore) != EOF) {
        count++;
    }
    fclose(fp);
    return count;
}

// 计算学生的总评成绩
void calculate_tscore(Student *students, int count) {
    for (int i = 0; i < count; i++) {
        students[i].tscore = (int)(students[i].pscore * 0.4 + students[i].fscore * 0.6 + 0.5);
    }
}

// 按总评成绩降序排列
void sort_students(Student *students, int count) {
    Student temp;
    for (int i = 0; i < count - 1; i++) {
        for (int j = i + 1; j < count; j++) {
            if (students[j].tscore > students[i].tscore) {
                temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }
}

// 将学生信息保存至文件
void save_students(Student *students, int count, const char *filename) {
    FILE *fp;
    fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("Failed to open file %s", filename);
        exit(1);
    }
    // 将学生信息写入文件
    fprintf(fp, "学号,平时成绩,期末成绩,总评成绩\n");
    for (int i = 0; i < count; i++) {
        fprintf(fp, "%s,%d,%d,%d\n", students[i].id, students[i].pscore, students[i].fscore, students[i].tscore);
    }
    fclose(fp);
}

int main() {
    Student students[MAX_STUDENTS];
    int count;
    count = read_students(students, "score.txt");
    calculate_tscore(students, count);
    sort_students(students, count);
    save_students(students, count, "result.txt");
    return 0;
}

注：在读取文件时，使用了"%[^,]"这个格式字符串，表示读取除逗号之外的所有字符，避免了因为读取到逗号而出现错误的情况。