程序可以运行，结果也对，但是程序结束的时候会访问冲突的错误，把stu2.readfrom(filename)改成stu1.readfrom(filename)就不会报错

void readfrom(char filename[])
{
ifstream read;
read.open(filename, ios::in|ios::binary);
read.read((char *)this,sizeof(student));
read.close();
}
};
int main()
{
student stu1, stu2;
char filename[1024];
stu1.input();
cout << "输入文件名";
cin >> filename;
stu1.writeto(filename);
stu2.readfrom(filename);
stu2.output();
return 0;