求大佬帮看看到底哪出问题了

学校的作业
和chatgtp联手写了四五十分钟还是这样
源代码放在一楼

#include <stdio.h>
#include <stdlib.h>
struct student
{
int num;
char name[20];
int math;
int eng;
int C;
};
void sort_by_average(struct student *stu, float *av, int n)
{
for (int i = 0; i < n - 1; i++)
{
for (int j = 0; j < n - i - 1; j++)
{
if (av[j] < av[j + 1])
{
float temp = av[j];
av[j] = av[j + 1];
av[j + 1] = temp;
// 交換學生結構體
struct student temp_stu = stu[j];
stu[j] = stu[j + 1];
stu[j + 1] = temp_stu;
}
}
}
}
float ave(int math, int eng, int C)
{
return (math + eng + C) / 3.0;
}
void write_to_file_and_screen(struct student *stu, float *av, int n)
{
FILE *fp;
fp = fopen("score_avg.txt", "w");
if (fp == NULL)
{
printf("无法打开文件！\n");
return;
}
printf("学号\t姓名\t数学\t英语\tC语言\t平均分\n");
fprintf(fp, "学号\t姓名\t数学\t英语\tC语言\t平均分\n");
for (int i = 0; i < n; i++)
{
printf("%d\t%s\t%d\t%d\t%d\t%.2f\n", stu.num, stu.name, stu.math, stu.eng, stu.C, av);
fprintf(fp, "%d\t%s\t%d\t%d\t%d\t%.2f\n", stu.num, stu.name, stu.math, stu.eng, stu.C, av);
}
fclose(fp);
}
int main()
{
int n;
printf("共有几位学生？");
scanf("%d", &n);
struct student *stu = (struct student *)malloc(n * sizeof(struct student));
if (stu == NULL)
{
printf("內存分配失敗！\n");
return 1;
}
FILE* fp;
fp = fopen("score.txt","r");
if (fp == NULL)
{
printf("无法打开文件！\n");
free(stu); // 释放动态分配的内存
return 1;
}
float av[20];
for(int i = 0; i < n; i++)
{
fscanf(fp, "%d %s %d %d %d", &stu.num, stu.name, &stu.math, &stu.eng, &stu.C);
av = ave(stu.math, stu.eng, stu.C);
}
fclose(fp);
sort_by_average(stu, av, n);
write_to_file_and_screen(s

tu, av, n);
// 释放动态分配的内存
free(stu);
return 0;
}

看一下你的score.txt，感觉你是把那行中文也打进去了

你要吗，我们最后一次作业是这个

好像比你们作业多一些要求，你看着改改就好了

宇宙主宰的电脑