实验内容：
为Linux系统设计一个简单的二级文件系统。要求做到以下几点：
（1）可以实现下列几条命令
login 用户登录
dir 列文件目录
create 创建文件
delete 删除文件
open 打开文件
close 关闭文件
read 读文件
write 写文件
（2）列目录时要列出文件名、物理地址、保护码和文件长度；
（3）源文件可以进行读写保护。
二级文件系统
代码：
#include <iostream>
#include <string>
using namespace std;
//假设一个磁盘的每个物理块大小为512个字节
struct MFD // 16个用户
{
string username;
string password;
//int pufd; //用户目录文件所在的物理块
struct USER_UFD * next; //指向用户目录
};
struct UFD //一个用户可以用16个文件夹，然后每个文件夹下可以有16个文件
{
struct file_message
{
string filename;
int protect_code; //保护码
int length; //文件长度
int addr; //存放该文件的物理块的第一个的快号
}ufd[16];
string directname; //用户目录名
int cur_file_size = 0; //不能在结构体内附初始值。好像不能成功
};
struct UOF //假设一个用户最多打开16个文件
{
struct uof
{
string filename;
int pointer; //文件的读写指针,其实就是文件的大小
int protect_code; //2表示可读可写,1表示可读不可写， 0表示不可读不可写
int addr; //存放文件的第一个磁盘块号
}uof[16];
int cur_openfilesize = 0;
};
struct fat //文件分配表 用一块物理块存放，那么最多可以记录64块数据块的信息。
{
int next = -1; //下一个磁盘块号
int used = 0; //1表示被使用，
// int self; //自己的快号
}fat[64];
struct USER_UFD
{
struct UFD direct[16]; //每个用户最多有16个目录
int cur_user_direct_size = 0; //当前用户的目录数
};
struct USER_UFD cur_user_all_direct_array[16]; //16个用户的所有目录的对象
int max_usersize = 16;
int max_userfilesize = 16;
int max_openfilesize = 16;
struct MFD cur_user; //当前用户
//struct UFD cur_user_dirtect[16]; //用户目录
struct UOF * cur_opentable; //当前文件打开表
char *fdisk; //虚拟磁盘的起始位置
struct UOF openfile[16]; //每一个用户对应一个文件打开表对象，只能设置为全局变量
MFD mfd[16]; //16个用户
int cur_user_size = 0; //记录当前用户的人数
string path; //记录当前用户的路径
//函数声明
int open(string name);
void register_user();
void remove(string);
int create(string);
int open(string);
int close(string);
int del(string);
int read(string);
int write(string, char *, int);
void dir();
int login();
void cd();
void mkdir(string);
void input_operation();
void register_user();
void remove(string name);
int create(string name)
{
//cout << cur_user.next->cur_file_size << endl;
//system("pause");
int index; //标识当前目录在direct数组中第几个
for (index = 0; index < cur_user.next->cur_user_direct_size; index++)
{
if (path == cur_user.next->direct[index].directname)
{
break;
}
}
int i;
for (i = 0; i < cur_user.next->direct[index].cur_file_size; i++) //遍历当前目录，查看是否有文件重名
{
if (name == cur_user.next->direct[index].ufd[i].filename)
break;
}
if (i < cur_user.next->direct[index].cur_file_size) //判断文件名是否重复
{
cout << "文件名重复" << endl;
return -1;
}
if (cur_user.next->direct[index].cur_file_size == 16) //判断当前目录的文件到达16个
{
cout << "用户文件已经达到16个" << endl;
return -1;
}
int j;
for (j = 0; j < 64; j++) //判断是否有空的空闲块。
{
if (fat[j].used == 0)
break;
}
if (j >= 64)
{
cout << "磁盘没有空闲块了" << endl;
return -1;
}
cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size].filename = name;
cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size].addr = j; //文件起始盘块号
cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size].length = 0;
cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size].protect_code = 2; //表示可读可写
cur_user.next->direct[index].cur_file_size++;//用户文件数量加1
fat[j].used = 1; //被使用
fat[j].next = -1; //只是个空文件,所有没有后序的块
//写入文件打开表中,就是调用open（）
cout << "文件创建成功" << endl;
int fd = open(name);
return fd;
}
int open(string name)
{
int index; //标识当前目录在direct数组中第几个
for (index = 0; index < cur_user.next->cur_user_direct_size; index++)
{
if (path == cur_user.next->direct[index].directname)
{
break;
}
}
int i;
for (i = 0; i < cur_user.next->direct[index].cur_file_size; i++) //当前目录有没有这个文件，没有就自然不能打开
{
if (name == cur_user.next->direct[index].ufd[i].filename)
break;
}
if (i > cur_user.next->direct[index].cur_file_size)
{
cout << "i的值为" << i << endl;
cout << "该用户没有这个文件" << endl;
return -1;
}
if (cur_opentable->cur_openfilesize == max_openfilesize) //如果打开文件的数量达到最大值，那么就无法打开
{
cout << "文件打开数量已经达到最大值" << endl;
return -1;
}
for (int j = 0; j < cur_opentable->cur_openfilesize; j++) //如果文件已经打开，就无需打开
{
if (cur_opentable->uof[j].filename == name)
{
cout << "文件已经打开" << endl;
return -1;
}
}
int k;
for (k = 0; k < cur_user.next->direct[index].cur_file_size; k++) //找到要打开的文件在文件数组中的第几个
{
if (cur_user.next->direct[index].ufd[k].filename == name)
break;
}
cur_opentable->uof[cur_opentable->cur_openfilesize].filename = name;
cur_opentable->uof[cur_opentable->cur_openfilesize].protect_code = cur_user.next->direct[index].ufd[k].protect_code;
cur_opentable->uof[cur_opentable->cur_openfilesize].pointer = cur_user.next->direct[index].ufd[k].length;
cur_opentable->uof[cur_opentable->cur_openfilesize].addr = cur_user.next->direct[index].ufd[k].addr;
cur_opentable->cur_openfilesize++; //文件打开数量加1
cout << "文件打开成功" << endl;
return k; //返回文件在文件打开表中的第几项
}
int close(string name)
{
int fd;
for (int i = 0; i < cur_opentable->cur_openfilesize; i++) //找到要关闭的文件在表中的第几项
{
if (cur_opentable->uof[i].filename == name)
{
fd = i;
break;
}
}
if (fd >= cur_opentable->cur_openfilesize)
{
cout << "没有这个文件或者文件没有打开" << endl;
return -1;
}
//将要删除的项目与最后一个项目交换,因为是数组存放，。。
cur_opentable->uof[fd].filename = cur_opentable->uof[cur_opentable->cur_openfilesize - 1].filename;
cur_opentable->uof[fd].pointer = cur_opentable->uof[cur_opentable->cur_openfilesize - 1].pointer;
cur_opentable->uof[fd].protect_code = cur_opentable->uof[cur_opentable->cur_openfilesize - 1].protect_code;
cur_opentable->uof[fd].addr = cur_opentable->uof[cur_opentable->cur_openfilesize - 1].addr;
//cur_opentable->cur_openfilesize--;
cur_opentable->cur_openfilesize--;
cout << "文件关闭成功" << endl;
return 0;
}
int del(string name) //删除文件打开表的文件数量不用减一，因为文件打开就不能删除文件
{
int index; //标识当前目录在direct数组中第几个
for (index = 0; index < cur_user.next->cur_user_direct_size; index++)
{
if (path == cur_user.next->direct[index].directname)
{
break;
}
}
int i;
for (i = 0; i < cur_user.next->direct[index].cur_file_size; i++) //判断当前目录下有没有这个文件
{
if (cur_user.next->direct[index].ufd[i].filename == name)
break;
}
if (i >= cur_user.next->direct[index].cur_file_size)
{
cout << "没有这个文件" << endl;
return -1;
}
int j;
for (j = 0; j < cur_opentable->cur_openfilesize; j++) //判断该文件是否被打开
{
if (cur_opentable->uof[j].filename == name)
break;
}
if (j < cur_opentable->cur_openfilesize) //说明文件被打开了
{
cout << "这个文件被打开了，请先关闭" << endl;
return -1;
}
//更新当前用户目录下文件数组信息,就是将最后一个文件的信息替换到要删除的文件的位置
fat[cur_user.next->direct[index].ufd[i].addr].used = 0; //没有使用
cur_user.next->direct[index].ufd[i].filename = cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size - 1].filename;
cur_user.next->direct[index].ufd[i].addr = cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size - 1].addr;
cur_user.next->direct[index].ufd[i].length = cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size - 1].length;
cur_user.next->direct[index].ufd[i].protect_code = cur_user.next->direct[index].ufd[cur_user.next->direct[index].cur_file_size - 1].protect_code;
cur_user.next->direct[index].cur_file_size--; //用户文件数量减1
//回收磁盘
int temp = fat[cur_user.next->direct[index].ufd[i].addr].next;
while (temp != -1)
{
fat[temp].used = 0;
temp = fat[temp].next;
}
cout << "删除文件成功" << endl;
return 0;
}
int read(string name)
{
int index1; //标识当前目录在direct数组中第几个
for (index1 = 0; index1 < cur_user.next->cur_user_direct_size; index1++)
{
if (path == cur_user.next->direct[index1].directname)
{
break;
}
}
int a;
for (a = 0; a < cur_user.next->direct[index1].cur_file_size; a++) //判断文件是否存在
{
if (cur_user.next->direct[index1].ufd[a].filename == name)
break;
}
if (a >= cur_user.next->direct[index1].cur_file_size)
{
cout << "没有这个文件" << endl;
return -1;
}
int i;
//判读文件是否打开
for (i = 0; i < cur_opentable->cur_openfilesize; i++)
{
if (cur_opentable->uof[i].filename == name)
break;
}
if (i >= cur_opentable->cur_openfilesize)
{
cout << "文件没有打开， 无法读取" << endl;
return -1;
}
int fd = i; //获取文件描述字
//判断读文件的合法性
if (cur_opentable->uof[fd].protect_code == 0) //我们创建的文件都是默认可读可写的。。。
{
cout << "文件不可读" << endl;
return -1;
}
else
{
int len = cur_opentable->uof[fd].pointer; //文件的长度
int block_size = len / 512; //磁盘的个数
int offset = len % 512; //偏移量
if (offset != 0)
block_size++;
//如果我用一个文件表示磁盘的引导块，用另一个文件表示磁盘的数据块，那么我们计算文件的起始位置就不用加上磁盘的引导块了吧。。
//关于文件的存放文件，我们char *fdisk表示一整个磁盘，然后不同文件的内容存放在这个指针所指向的不同字符段
char * first = fdisk + cur_opentable->uof[fd].addr * 512; //文件的起始地址
char * buf = (char *)malloc(512 * sizeof(char)); //缓冲区
cout << "文件的内容为 :";
for (int k = 0; k < block_size; k++)
{
if (k == block_size - 1) //则是最后一个磁盘块
{
for (int j = 0; j < len - k * 512; j++) //赋值文件剩余的字符，其实就是偏移量
{
buf[j + k * 512] = first[j];
}
for (int u = 0; u < len - k * 512; u++)
{
cout << buf[u + k * 512]; //输出剩余长度，之所以这样输出，printf()，将整个buf的内容全部输出，如果没有读满就出现乱码啦。。
}
}
else //不在最后一个磁盘块，也就是在其他已经读满的磁盘块
{
for (int j = 0; j < len - i * 512; j++)
buf[j + k * 512] = first[j]; //缓冲区读满就输出内容
printf("%s\n", buf); //输出文件的内容
int next_block = fat[cur_opentable->uof[fd].addr].next; //读完一个磁盘块后，在接着读下一个磁盘块
first = fdisk + next_block * 512;
}
}
cout << endl;
cout << "文件读取成功" << endl;
free(buf); //释放缓冲区
return 0;
}
}
//类似于文件拷贝实验，每次赋值缓冲区到虚拟磁盘中,
//待完成问题：更新表的文件长度
int write(string name, char * buf, int len)
{
int index1; //标识当前目录在direct数组中第几个
for (index1 = 0; index1 < cur_user.next->cur_user_direct_size; index1++)
{
if (path == cur_user.next->direct[index1].directname)
{
break;
}
}
int i;
//判读文件是否打开
for (i = 0; i < cur_opentable->cur_openfilesize; i++)
{
if (cur_opentable->uof[i].filename == name)
break;
}
if (i >= cur_opentable->cur_openfilesize)
{
cout << "文件没有打开， 无法读取" << endl;
return -1;
}
int fd = i; //获取文件描述字
//判断读文件的合法性
if (cur_opentable->uof[fd].protect_code != 2)
{
cout << "文件不可写" << endl;
return -1;
}
else
{
int temp; //保存当前所写的文件在用户文件目录表的第几项，为了后面修改文件的大小
int first_block = cur_opentable->uof[fd].addr; //用户文件存放的第一个磁盘块
for (int k = 0; k < cur_user.next->direct[index1].cur_file_size; k++)
{
if (cur_user.next->direct[index1].ufd[k].addr == first_block)
{
temp = k;
break;
}
}
//追加写
//找到该文件存放的最后一个磁盘块
while (fat[first_block].next != -1)
{
first_block = fat[first_block].next;
}
//计算该文件存放的最后一个地址
char * first;
first = fdisk + first_block * 512 + cur_opentable->uof[fd].pointer % 512;
//如果最后一个文件剩下的空间大于要写入的长度
if (len <= 512 - cur_opentable->uof[fd].pointer % 512)
{
//strcpy(first, buf); 这句代码出现问题，可能是由于buf没有读满，后面的值被访问了，非法！
for (int i = 0; i < len; i++)
{
first[i] = buf[i];//将缓冲区的内容写入虚拟磁盘中
}
cur_opentable->uof[fd].pointer = cur_opentable->uof[fd].pointer + len; //更新文件打开表
cur_user.next->direct[index1].ufd[temp].length = cur_user.next->direct[index1].ufd[temp].length + len; //更新用户目录文件表
}
else //如果剩下的空间不足写入
{
for (i = 0; i < 512 - cur_opentable->uof[fd].pointer % 512; i++)
{ //写入一部分的内容到最后一个磁盘块的剩余空间
first[i] = buf[i];
}
//计算分配完最后一个磁盘的剩余空间后，还剩下多少字节没有存储
int last_size = len - (512 - cur_opentable->uof[fd].pointer % 512);
int need_block_size = last_size / 512;
int need_offset_size = last_size % 512;
if (need_offset_size > 0)
need_block_size++; //总共需要这么磁盘块
int unused_block_size = 0; //记录没有使用过的磁盘块的个数
//int first_unused_block; //记录第一个没有被使用过的磁盘
int flag = 0;
for (int i = 0; i < 64; i++)
{
if (fat[i].used == 0)
{
unused_block_size++;
}
}
if (unused_block_size < need_block_size)
{
cout << "磁盘没有空间存放了-=-=" << endl;
return -1;
}
else
{
int item = cur_opentable->uof[fd].addr;
for (int p = 0; p < need_block_size; p++) //执行多次寻找空闲磁盘的操作，
{
for (int i = 0; i < 64; i++)
{
if (fat[i].used == 0) //没有被使用
{
first = fdisk + i * 512; //当前要写入的磁盘块的起始地址
fat[i].used = 1; //标记被使用
fat[item].next = i; //标记下一个磁盘
item = i;
break;
}
}
if (p == need_block_size - 1)
{
for (int k = 0; k < need_offset_size; k++) //将文件的偏移量写入最后一个文件中
first[k] = buf[k];
//更新最后一个磁盘块的next值
fat[i].next = -1;
}
else //如果不是最后一个空闲块
{ //待解决问题，就是如果更新fat的next值
for (int k = 0; k < 512; k++)
first[k] = buf[k];
}
}
cur_opentable->uof[fd].pointer = cur_opentable->uof[fd].pointer + last_size; //更新文件打开表
cur_user.next->direct[index1].ufd[temp].length = cur_user.next->direct[index1].ufd[temp].length + last_size; //更新用户目录文件表
}
}
cout << "文件写入成功" << endl;
return 0;
}
}
void dir()
{
int index1; //标识当前目录在direct数组中第几个
for (index1 = 0; index1 < cur_user.next->cur_user_direct_size; index1++)
{
if (path == cur_user.next->direct[index1].directname)
{
break;
}
}
if (path == "") //表示此时路径在用户的目录表，显示文件目录
{
cout << "\t" << "目录名" << endl;
for (int i = 0; i < cur_user.next->cur_user_direct_size; i++)
{
cout << "\t" << cur_user.next->direct[i].directname << endl;
}
}
else //显示目录下的文件
{
cout << "\t" << "文件名" << "\t" << "文件保护码" << "\t" << "文件长度" << "\t" <<"文件起始盘块号" << endl;
for (int i = 0; i < cur_user.next->direct[index1].cur_file_size; i++) //输出文件的信息
{
cout << "\t" << cur_user.next->direct[index1].ufd[i].filename << "\t" << cur_user.next->direct[index1].ufd[i].protect_code << "\t" << "\t" << cur_user.next->direct[index1].ufd[i].length <<"\t" << "\t" << cur_user.next->direct[index1].ufd[i].addr << endl;
}
}
}
int login()
{
string name;
string password;
//UFD user;
cout << "请输入你的姓名" << endl;
cin >> name;
cout << "请输入你的密码" << endl;
cin >> password;
int i;
for ( i = 0; i < cur_user_size; i++)
{
if (mfd[i].username == name && mfd[i].password == password)
{
break;
}
}
if (i >= cur_user_size)
{
cout << "没有这个用户或者用户名密码错误" << endl;
return -1;
}
mfd[i].next = & (cur_user_all_direct_array[i]); //用户指向自己的所有目录的结构
//初始化当前用户的信息
cur_user = mfd[i];
cur_user.next->cur_user_direct_size = mfd[i].next->cur_user_direct_size; //
cur_user_size++; //用户人数++
cur_opentable = &openfile[cur_user_size]; //指针指向文件打开表对象
cur_opentable->cur_openfilesize = 0; //设初始值
path = ""; //指定当前路径为用户的全部目录处
return 1;
}
void cd()
{
string temp_path;
cin >> temp_path;
if (temp_path == "..")
{
path = "";
return;
}
int i;
for (i = 0; i < cur_user.next->cur_user_direct_size; i++) //判断path是否存在
{
if (temp_path == cur_user.next->direct[i].directname)
break;
}
if (i >= cur_user.next->cur_user_direct_size)
{
cout << "没有这个目录" << endl;
return;
}
path = temp_path;
return;
}
void mkdir(string name)
{
if (cur_user.next->cur_user_direct_size == 16)
{
cout << "用户目录已经达到最大值，不能在创建目录了" << endl;
return;
}
int i;
for (i = 0; i < cur_user.next->cur_user_direct_size; i++) //判断创建的目录是否存在
{
if (cur_user.next->direct[i].directname == name)
break;
}
if (i < cur_user.next->cur_user_direct_size)
{
cout << "该目录已经存在了" << endl;
return;
}
cur_user.next->direct[cur_user.next->cur_user_direct_size].directname = name;
cur_user.next->direct[cur_user.next->cur_user_direct_size].cur_file_size = 0; //新创建的目录里面的文件个数为0
cur_user.next->cur_user_direct_size++; //用户的目录数加1
cout << "创建目录成功" << endl;
return;
}
void input_operation() //用户输入命令
{
if (cur_user.username == "")
cout << "localhost :";
else
cout << cur_user.username << "@localhost home/" <<path << "：";
string operation;
cin >> operation;
if (operation == "login")
{
login();
}
else if (operation == "dir")
dir();
else if (operation == "create")
{
string filename;
cin >> filename;
create(filename);
}
else if (operation == "del")
{
string filename;
cin >> filename;
del(filename);
}
else if (operation == "open")
{
string name;
cin >> name;
open(name);
}
else if (operation == "close")
{
string name;
cin >> name;
close(name);
}
else if (operation == "read")
{
string name;
cin >> name;
read(name);
}
else if (operation == "write")
{
string content;
string name;
cout << "请输入要写入的文件：";
cin >> name;
cin.ignore(); //清空缓冲区的内容，不然getline读到上一个回车直接结束。。。
cout << "请输入文件要写入的内容: " << endl;;
getline(cin, content); //读入一整行内容
//cout << content << endl;
//system("pause");
//cin >> content;
char buf[512];
int times = content.length() / 512;
int offset = content.length() % 512;
if (offset != 0)
times++;
for (int i = 0; i < times; i++)
{
if (i == times - 1) //注意这里不能写成times-- o.o!!!
{
for (int j = 0; j < offset; j++)
buf[j] = content[j];
}
else
{
for (int j = 0; j < 512; j++)
buf[j] = content[j];
}
write(name, buf, content.length());
}
}
else if (operation == "exit")
{
exit(0);
}
else if (operation == "cd")
{
cd();
}
else if (operation == "mkdir")
{
string name;
cin >> name;
mkdir(name);
}
else if (operation == "register")
{
register_user();
}
else if (operation == "remove")
{
string name;
cin >> name;
remove(name);
}
else
{
cout << "你的命令错误，重新输入" << endl;
}
}
void register_user() //注册用户
{
cout << "请输入用户名：";
string username;
cin >> username;
cout << "请输入密码：";
string password;
cin >> password;
int i;
for (i = 0; i < 16; i++)
{
if (mfd[i].username == username)
{
break;
}
}
if (i < 16)
{
cout << "该用户已经存在" << endl;
return;
}
mfd[cur_user_size].username = username;
mfd[cur_user_size].password = password;
cur_user_size++; //用户人数加1
cout << "用户注册成功！" << endl;
}
void remove(string name) //删除目录
{
int index;
for (int i = 0; i < cur_user.next->cur_user_direct_size; i++)
{
if (name == cur_user.next->direct[i].directname)
{
index = i;
break;
}
}
for (int i = 0; i < cur_user.next->direct[index].cur_file_size; i++) //删除目录里面的文件
{//直接释这些文件所占的磁盘块
fat[cur_user.next->direct[index].ufd[i].addr].used = 0; //没有使用
int temp = fat[cur_user.next->direct[index].ufd[i].addr].next;
while (temp != -1)
{
fat[temp].used = 0;
temp = fat[temp].next;
}
}
//删除目录项，就是将两个目录项的内容进行交换
cur_user.next->direct[index].cur_file_size = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].cur_file_size; //注意这里需要减一，由于本身结构的限制
cur_user.next->direct[index].directname = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].directname;
for (int i = 0; i < cur_user.next->direct[cur_user.next->cur_user_direct_size-1].cur_file_size; i++) //注意这里的减一
{
cur_user.next->direct[index].ufd[i].addr = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].ufd[i].addr;
cur_user.next->direct[index].ufd[i].filename = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].ufd[i].filename;
cur_user.next->direct[index].ufd[i].length = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].ufd[i].length;
cur_user.next->direct[index].ufd[i].protect_code = cur_user.next->direct[cur_user.next->cur_user_direct_size-1].ufd[i].protect_code;
}
cur_user.next->cur_user_direct_size--; //目录数量减1
cout << "删除目录成功" << endl;
return;
}
int main()
{
cur_user.username = ""; //初始化当前用户的用户名为空
path = "";
//用内存模拟外存，申请内存空间
fdisk = (char *)malloc(1024 * 1024 * sizeof(char)); //初始换fdisk
cout << "***************欢迎来到二级文件系统******************" << endl;
cout << "\t" << "\t" << "命令" << "\t" << "\t" << "功能" << endl;
cout << "\t" << "\t" << "register" << "\t" << "注册" << endl;
cout << "\t" << "\t" << "login" << "\t" << "\t" << "登录" << endl;
cout << "\t" << "\t" << "create" << "\t" << "\t" << "创建文件" << endl;
cout << "\t" << "\t" << "mkdir" << "\t" << "\t" << "创建目录" << endl;
cout << "\t" << "\t" << "cd" << "\t" << "\t" << "切换目录" << endl;
cout << "\t" << "\t" << "open" << "\t" << "\t" << "打开文件" << endl;
cout << "\t" << "\t" << "close" << "\t" << "\t" << "关闭文件" << endl;
cout << "\t" << "\t" << "read" << "\t" << "\t" << "读文件" << endl;
cout << "\t" << "\t" << "write" << "\t" << "\t" << "写文件" << endl;
cout << "\t" << "\t" << "del" << "\t" << "\t" << "删除文件" << endl;
cout << "\t" << "\t" << "exit" << "\t" << "\t" << "退出系统" << endl;
cout << "*****************************************************" << endl;
while (true)
input_operation();
}
//有个问题，循环的界值要更新。--》》解决
//出现问题：指向一些空指针的问题-->解决
