实验四 文件系统实验

1、实验四 文件系统实验一 .   目的要求  1、用高级语言编写和调试一个简单的文件系统，模拟文件管理的工作过程。从而对各种文件操作命令的实质内容和执行过程有比较深入的了解。 2、要求设计一个 n个用户的文件系统，每次用户可保存m个文件，用户在一次运行中只能打开一个文件，对文件必须设置保护措施，且至少有Create、delete、open、close、read、write等命令。二 .   例题： 1、设计一个10个用户的文件系统，每次用户可保存10个文件，一次运行用户可以打开5个文件。2、程序采用二级文件目录（即设置主目录MFD）和用户文件目录（UED）。另外，为

2、打开文件设置了运行文件目录（AFD）。3、为了便于实现，对文件的读写作了简化，在执行读写命令时，只需改读写指针，并不进行实际的读写操作。4、算法与框图：  因系统小，文件目录的检索使用了简单的线性搜索。 文件保护简单使用了三位保护码：允许读写执行、对应位为 1，对应位为0，则表示不允许读写、执行。 程序中使用的主要设计结构如下：   主文件目录和用户文件目录（ MFD、UFD）   打开文件目录（ AFD）（即运行文件目录）M D FU F DA F D用户名文件名打开文件名文件目录指针保护码打开保护码用户名文件长度读写指针文件目录指针文件名··

3、;文件系统算法的流程图如下：三 .   实验题：  1、 增加 23个文件操作命令，并加以实现。（如移动读写指针，改变文件属性，更换文件名，改变文件保护级别）。代码如下：/1、增加 23个文件操作命令，并加以实现。（如移动读写指针，改变文件属性，更换文件名，改变文件保护级别）。#include<iostream>#include<string>#include<conio.h>using namespace std;struct TYPE_UFD stringFile_Name; boolRead; boolWrite; boolExec

4、ute; intLength_File;struct TYPE_MFD stringUser_Name; TYPE_UFD*Pointer;struct TYPE_AFD intFile_ID; boolRead; boolWrite; boolExecute; intPointer;class TYPE_FILE_SYSTEMpublic: void Initial( void ); void Start( void );private: int_Number_Users; int_Number_Files; int_MaxNumber_Open_Files; TYPE_MFD *_MFD;

5、 TYPE_UFD *_UFD; TYPE_AFD *_AFD;void TYPE_FILE_SYSTEM:Initial( void ) _Number_Users = 10; _Number_Files = 10; _MaxNumber_Open_Files = 5; _UFD = new TYPE_UFD _Number_Users*_Number_Files; _MFD = new TYPE_MFD _Number_Users; int i=0; for( i=0 ; i<_Number_Users ; i+ ) _MFDi.Pointer = &(_UFDi*_Numb

6、er_Files); _AFD = new TYPE_AFD _MaxNumber_Open_Files; _MFD0.User_Name = "zaq" _UFD0.File_Name = "file1.txt" _UFD0.Length_File = 10; _UFD0.Read = true; _UFD0.Write = false; _UFD0.Execute = true; _UFD1.File_Name = "file2.txt" _UFD1.Length_File = 20; _UFD1.Read = true; _UF

7、D1.Write = false; _UFD1.Execute = false; for( i=2 ; i<_Number_Files ; i+ ) _UFDi.File_Name = "" _UFDi.Length_File = -1; _UFDi.Read = false; _UFDi.Write = false; _UFDi.Execute = false; void TYPE_FILE_SYSTEM:Start( void ) int User_ID; int i,temp_int; string temp; char choice; int Number_O

8、pen_Files; string User_Name; string Command; TYPE_UFD *UFD; do do cout << "已创建用户名为zaqn指令有：create delete open dir diropen write read logout shutdown nn" cout << "请输入用户名:" cin >> User_Name; for( User_ID=0 ; User_ID<_Number_Users ; User_ID+ ) if( _MFDUser_ID.Use

9、r_Name = User_Name ) break; if( User_ID = _Number_Users ) cout << "用户名错误，请再次输入 ." << endl; while( User_ID = _Number_Users ); cout << "欢迎登录 , " << User_Name << " !" << endl; UFD = _MFDUser_ID.Pointer; for( i=0 ; i<_MaxNumber_Open_Fi

10、les ; i+ ) _AFDi.File_ID = -1; Number_Open_Files = 0; do cout << "C:" << User_Name << ">" ; cin >> Command; if( Command = "dir" ) cout << endl; cout << "打开用户 " << User_Name <<"的文件 " << endl; co

11、ut << "t" << "Statet" << "Lengtht" << "File name" << endl; for( i=0 ; i<_Number_Files ; i+ ) if( UFDi.Length_File != -1 ) cout << "t" ; if( UFDi.Read = true ) cout << "R" else cout << "

12、;-" if( UFDi.Write = true ) cout << "W" else cout << "-" if( UFDi.Execute = true ) cout << "E" else cout << "-" cout << "t" cout << UFDi.Length_File; cout << "t" cout << UFDi.File_Name &l

13、t;< endl; cout << endl; else if( Command = "diropen" ) cout << endl; cout << "打开用户 " << User_Name << "的文件 " <<endl; cout << "t" << "Statet" << "Open File name" << endl; for( i=0

14、 ; i<_MaxNumber_Open_Files ; i+ ) if( _AFDi.File_ID != -1 ) cout << "t" ; if( _AFDi.Read = true ) cout << "R" else cout << "-" if( _AFDi.Write = true ) cout << "W" else cout << "-" if( _AFDi.Execute = true ) cout <

15、< "E" else cout << "-" cout << "t" cout << UFD_AFDi.File_ID.File_Name << endl; cout << endl; else if( Command = "create" ) for( i=0 ; i<_Number_Files ; i+ ) if( UFDi.Length_File = -1 ) break; if( i = _Number_Files ) cout <

16、;< "Error: 已有名为 " << _Number_Files << " 的文件." << endl; else cout << "请输入新文件信息:" << endl; cout << "文件名 : " cin >> temp; UFDi.File_Name = temp; cout << "文件权限 : " cout << "Read (y/n):" d

17、o choice = getch(); while( choice!='y' && choice!='n' ); if( choice = 'y' ) UFDi.Read = true; else UFDi.Read = false; cout << endl; cout << "Write (y/n):" do choice = getch(); while( choice!='y' && choice!='n' ); if( choic

18、e = 'y' ) UFDi.Write = true; else UFDi.Write = false; cout << endl; cout << "Execute (y/n):" do choice = getch(); while( choice!='y' && choice!='n' ); if( choice = 'y' ) UFDi.Execute = true; else UFDi.Execute = false; cout << endl;

19、cout << "Length :" cin >> temp_int; if( temp_int > 0 ) UFDi.Length_File = temp_int; cout << "新文件 " << UFDi.File_Name << " 已建立!" << endl; else if( Command = "delete" ) cout << "请输入文件名 :" cin >> temp;

20、for( i=0 ; i<_Number_Files ; i+ ) if( (UFDi.Length_File!=-1)&&(UFDi.File_Name=temp) ) break; if( i = _Number_Files ) cout << "文件名错误，请再次输入 ." << endl; else UFDi.Length_File = -1; cout << "文件 " << UFDi.File_Name << " 已删除 ." <<

21、; endl; else if( Command = "open" ) if( Number_Open_Files = _MaxNumber_Open_Files ) cout << "Error: 你已经打开了 " << Number_Open_Files << " 文件." << endl; else cout << "请输入文件名:" cin >> temp; for( i=0 ; i<_Number_Files ; i+ ) if

22、( (UFDi.Length_File!=-1)&&(UFDi.File_Name=temp) ) break; if( i = _Number_Files ) cout << "文件名错误，请再次输入 ." << endl; else Number_Open_Files+; for( temp_int=0 ; temp_int<_MaxNumber_Open_Files ; temp_int+ ) if( _AFDtemp_int.File_ID = -1 ) break; _AFDtemp_int.File_ID = i;

23、_AFDtemp_int.Pointer = 0; cout << "请定义打开方式 :" << endl; if( UFDi.Read = true ) cout << "Read (y/n):" do choice = getch(); while( choice!='y' && choice!='n' ); if( choice = 'y' ) _AFDtemp_int.Read = true; else _AFDtemp_int.Read = fa

24、lse; cout << endl; else _AFDtemp_int.Read = false; if( UFDi.Write = true ) cout << "Write (y/n):" do choice = getch(); while( choice!='y' && choice!='n' ); if( choice = 'y' ) _AFDtemp_int.Write = true; else _AFDtemp_int.Write = false; cout <&l

25、t; endl; else _AFDtemp_int.Write = false; if( UFDi.Execute = true ) cout << "Execute (y/n):" do choice = getch(); while( choice!='y' && choice!='n' ); if( choice = 'y' ) _AFDtemp_int.Execute = true; else _AFDtemp_int.Execute = false; cout << endl

26、; else _AFDtemp_int.Execute; cout << "文件 " << temp << " 已打开 ." << endl; else if( Command = "logout" ) cout << "再见 , " << User_Name << " !" << endl; break; else if( Command = "close" ) cout <

27、;< "请输入文件名 :" cin >> temp; for( i=0 ; i<_Number_Files ; i+ ) if( (UFDi.Length_File!=-1)&&(UFDi.File_Name=temp) ) break; if( i = _Number_Files ) cout << "文件名错误，请再次输入 ." << endl; else for( temp_int=0 ; temp_int<_MaxNumber_Open_Files ; temp_int+ )

28、if( _AFDtemp_int.File_ID = i ) break; if( temp_int = _MaxNumber_Open_Files ) cout << "文件 " << temp << " 未打开 ." << endl; else _AFDtemp_int.File_ID = -1; Number_Open_Files-; cout << "文件 " << temp << " 已关闭 ." << end

29、l; else if( Command = "read" ) cout << "请输入文件名 :" cin >> temp; for( i=0 ; i<_Number_Files ; i+ ) if( (UFDi.Length_File!=-1)&&(UFDi.File_Name=temp) ) break; if( i = _Number_Files ) cout << "文件名错误，请再次输入 ." << endl; else for( temp_int=0 ;

30、 temp_int<_MaxNumber_Open_Files ; temp_int+ ) if( _AFDtemp_int.File_ID = i ) break; if( temp_int = _MaxNumber_Open_Files ) cout << "文件 " << temp << " 未打开 ." << endl; else if( _AFDtemp_int.Read = true ) cout << "文件 " << temp <<

31、; " 成功读取." << endl; else cout << "Error: 文件打开模式错误 ." << endl; else if( Command = "write" ) cout << "请输入文件名 :" cin >> temp; for( i=0 ; i<_Number_Files ; i+ ) if( (UFDi.Length_File!=-1)&&(UFDi.File_Name=temp) ) break; if(

32、 i = _Number_Files ) cout << "文件名错误，请再次输入 ." << endl; else for( temp_int=0 ; temp_int<_MaxNumber_Open_Files ; temp_int+ ) if( _AFDtemp_int.File_ID = i ) break; if( temp_int = _MaxNumber_Open_Files ) cout << "文件 " << temp << " 未打开 ." <

33、< endl; else if( _AFDtemp_int.Write = true ) cout << "文件 " << temp << " 成功写入." << endl; else cout << "Error: 文件打开模式错误 ." << endl; else if( Command = "shutdown" ) cout << "正在注销." << endl; cout <<

34、; "再见 , " << User_Name << " !" << endl; cout << "正在关机." << endl; break; else cout << "指令错误，请再次输入 ." << endl; while( Command != "logout" && Command != "shutdown" ); while( Command != "sh

35、utdown" );int main() TYPE_FILE_SYSTEM FS; FS.Initial(); FS.Start(); return 0;2、 编一个通过屏幕选择命令的文件管理系统，每屏要为用户提供足够的选择信息，不需要打入冗长的命令。 代码如下：#include <iostream>using namespace std;/2、编一个通过屏幕选择命令的文件管理系统，每屏要为用户提供足够的选择信息，不需要打入冗长的命令。#include <stdio.h>#include <stdlib.h>#include <string.

36、h>#define getpch(type) (type*)malloc(sizeof(type)void Select();int userNum=0;struct mdf char userName20; struct ufd* p; mdf20;struct ufd char fileName20; char File50; struct ufd * next;*fp,*tp,*p,*begin;typedef struct ufd UFD;void show( UFD *f) begin=f; if(begin->next=NULL) printf("该用户名下尚

37、无文件！n"); else printf("该用户名下所有文件：n"); begin=begin->next; while(begin!=NULL) printf("%s: %sn",begin->fileName,begin->File); begin=begin->next; void Operation(UFD *f) int i; char filename20,file50; begin=f;label: printf("请选择操作：n 1:create; 2:delete; 3:read; 4:wr

38、ite; 5:open;n 6:close; 7:Chang File's Name; 8:Show All The Filen"); scanf("%d",&i); if(i=1) tp=getpch(UFD); printf("请输入文件名："); scanf("%s",filename); printf("n请输入文件内容："); scanf("%s",file); strcpy(tp->fileName,filename); strcpy(tp->F

39、ile,file); tp->next=NULL; p=begin; p->next=tp; printf("n文件创建完毕！n"); goto label; else if(i=2) printf("请输入文件名："); scanf("%s",filename); p=begin->next; while(strcmp(p->fileName,filename)!=0&&p!=NULL) p=p->next; if(p=NULL) printf("文件不存在！n");

40、 else tp=begin; while(tp->next!=p) tp=tp->next; tp->next=p->next; free(p); printf("文件已删除！n"); goto label; else if(i=3) printf("请输入文件名："); scanf("%s",filename); p=begin->next; while(strcmp(p->fileName,filename)!=0&&p!=NULL) p=p->next; if(p=NULL) printf("文件不存在！n"); else printf("%s: %sn",