请编写函数，从文件中读取成绩不及格的学生信息，将结果写入另一个文件。

这里提供Python代码实现：

def write_failing_students(input_file, output_file):
    with open(input_file, 'r') as f_in, open(output_file, 'w') as f_out:
        for line in f_in:
            student_info = line.strip().split()
            if int(student_info[1]) < 60: # 判断成绩是否不及格
                f_out.write(line)

函数`write_failing_students`接受两个参数，分别为输入文件路径和输出文件路径。函数通过`with`语句打开输入文件和输出文件，遍历输入文件的每一行，将学生信息转化为列表形式，并对成绩进行判断。如果成绩不及格，就将这一行信息写入输出文件中。最后，函数自动关闭文件。

相关问题

请用C语言编写函数，从文件中读取成绩不及格的学生信息，将结果写入另一个文件。

以下是一个可能的实现：

#include <stdio.h>

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

void write_failed_students(const char* input_filename, const char* output_filename) {
    FILE* input_file = fopen(input_filename, "r");
    if (input_file == NULL) {
        printf("Failed to open input file %s\n", input_filename);
        return;
    }
    
    FILE* output_file = fopen(output_filename, "w");
    if (output_file == NULL) {
        fclose(input_file);
        printf("Failed to open output file %s\n", output_filename);
        return;
    }
    
    Student student;
    while (fscanf(input_file, "%s %d", student.name, &student.score) != EOF) {
        if (student.score < 60) {
            fprintf(output_file, "%s %d\n", student.name, student.score);
        }
    }
    
    fclose(input_file);
    fclose(output_file);
}

int main() {
    write_failed_students("input.txt", "output.txt");
    return 0;
}

这个程序定义了一个 `Student` 结构体表示学生，包含一个名字和一个分数。`write_failed_students` 函数接受两个文件名参数，打开输入文件并逐行读取学生信息，如果该学生的分数不及格（小于60），则将该学生的信息写入输出文件。最后，两个文件都会被关闭。在 `main` 函数中，我们调用 `write_failed_students` 来执行这个操作。

用c语言写:姓名 高等数学 英语 计算机 电学 张三 98 77 88 67 李四 88 90 99 56 王五 67 76 58 77 关六 66 77 77 80（2）建立一个数据文件st.txt，将以上学生成绩数据写入文件中； （3）从文件st.txt中读数据，计算每个学生的总成绩，并按总成绩排序，结果写入文件st_s.dat中； （4）查找并输出不及格学生的姓名、相应的课程名和成绩。

以下是用C语言实现题目要求的代码：

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

#define MAX_STUDENT_NUM 100
#define SUBJECT_NUM 4

typedef struct {
    char name[20];
    int scores[SUBJECT_NUM];
    int total_score;
} Student;

void write_student_data_to_file(Student students[], int n, char* filename) {
    FILE* fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("Failed to open file %s for writing.\n", filename);
        exit(1);
    }
    for (int i = 0; i < n; i++) {
        fprintf(fp, "%s %d %d %d %d\n", students[i].name, students[i].scores[0], students[i].scores[1], students[i].scores[2], students[i].scores[3]);
    }
    fclose(fp);
    printf("Successfully wrote student data to file %s.\n", filename);
}

void read_student_data_from_file(Student students[], int* n, char* filename) {
    FILE* fp = fopen(filename, "r");
    if (fp == NULL) {
        printf("Failed to open file %s for reading.\n", filename);
        exit(1);
    }
    *n = 0;
    while (!feof(fp)) {
        fscanf(fp, "%s %d %d %d %d", students[*n].name, &students[*n].scores[0], &students[*n].scores[1], &students[*n].scores[2], &students[*n].scores[3]);
        int sum = 0;
        for (int i = 0; i < SUBJECT_NUM; i++) {
            sum += students[*n].scores[i];
        }
        students[*n].total_score = sum;
        (*n)++;
    }
    (*n)--;
    fclose(fp);
    printf("Successfully read student data from file %s.\n", filename);
}

void sort_students_by_total_score(Student students[], int n) {
    for (int i = 0; i < n - 1; i++) {
        for (int j = i + 1; j < n; j++) {
            if (students[i].total_score < students[j].total_score) {
                Student temp = students[i];
                students[i] = students[j];
                students[j] = temp;
            }
        }
    }
}

void write_sorted_student_data_to_file(Student students[], int n, char* filename) {
    FILE* fp = fopen(filename, "w");
    if (fp == NULL) {
        printf("Failed to open file %s for writing.\n", filename);
        exit(1);
    }
    for (int i = 0; i < n; i++) {
        fprintf(fp, "%s %d %d %d %d %d\n", students[i].name, students[i].scores[0], students[i].scores[1], students[i].scores[2], students[i].scores[3], students[i].total_score);
    }
    fclose(fp);
    printf("Successfully wrote sorted student data to file %s.\n", filename);
}

void find_failed_students(Student students[], int n) {
    printf("Failed students:\n");
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < SUBJECT_NUM; j++) {
            if (students[i].scores[j] < 60) {
                printf("%s %s %d\n", students[i].name, j == 0 ? "Math" : j == 1 ? "English" : j == 2 ? "Computer" : "Electric", students[i].scores[j]);
            }
        }
    }
}

int main() {
    Student students[MAX_STUDENT_NUM];
    int n = 4;
    strcpy(students[0].name, "张三");
    students[0].scores[0] = 98;
    students[0].scores[1] = 77;
    students[0].scores[2] = 88;
    students[0].scores[3] = 67;
    strcpy(students[1].name, "李四");
    students[1].scores[0] = 88;
    students[1].scores[1] = 90;
    students[1].scores[2] = 99;
    students[1].scores[3] = 56;
    strcpy(students[2].name, "王五");
    students[2].scores[0] = 67;
    students[2].scores[1] = 76;
    students[2].scores[2] = 58;
    students[2].scores[3] = 77;
    strcpy(students[3].name, "关六");
    students[3].scores[0] = 66;
    students[3].scores[1] = 77;
    students[3].scores[2] = 77;
    students[3].scores[3] = 80;

    write_student_data_to_file(students, n, "st.txt");

    read_student_data_from_file(students, &n, "st.txt");

    sort_students_by_total_score(students, n);

    write_sorted_student_data_to_file(students, n, "st_s.dat");

    find_failed_students(students, n);

    return 0;
}

其中，`write_student_data_to_file()`函数将学生数据写入文件；`read_student_data_from_file()`函数从文件中读取学生数据，并计算每个学生的总成绩；`sort_students_by_total_score()`函数按照总成绩对学生进行排序；`write_sorted_student_data_to_file()`函数将排序后的学生数据写入文件；`find_failed_students()`函数查找并输出不及格学生的姓名、相应的课程名和成绩。主函数中，我们先手动初始化了学生数据，然后调用上述函数完成题目要求。