#include
#include
#include
#include
#include?
#include?
#include?

#define?LEN?sizeof（struct?commandHistory）
#define?LEN1?sizeof（struct?savePath）

struct?commandHistory
{
????int?iOrder;
????char?*strDisplay_name;
????char?*strDirectory;
????struct?commandHistory?*next;
};

struct?savePath
{
????char?*path_name;
????struct?savePath?*next;
};


/*?Function?prototypes?*/
char?*?extractRoute_cd（char?*?const?char?*?int）;
char?*?extractRoute_path（char?*?const?char?*?int）;
struct?commandHistory?*?create_commandHistroy（int?char?*?char?*）;
void?display_History（struct?commandHistory?*）;
int?clear_History（struct?commandHistory*）;
struct?commandHistory?*??write_History（int??char?*?char?*?struct?commandHistory?*）;
void?display_singleHistory（int?int?struct?commandHistory?*）;
struct?savePath?*?create_path_head（char?*）;
void?write_Path（int?char?*?struct?savePath?*）;
struct?savePath?*?delete_path（char?*?struct?savePath?*）;
void?display_path（struct?savePath?*）;
int?execu_tion（char?*）;



int?main（int?argc?const?char?*?argv[]）?{
????char?*strCommand_name[6]?=?{?“exit““cd?““pwd““path““history“};?//add?a?“?“?to?each?command?so?that?the?program?can?know?if?the?format?is?wrong
????char?*strUser_command1;??????????//for?saving?user‘s?input
????char?strHistory_offset1[10]?=?“history?-c“;?????//for?“strcmp“?to?find?the?offset
????char?strUser_command[100];
????char?strNew_directory[100]?=?{0};?????????//for?saving?user‘s?file?route
????char?strOffset_empty[8]?=?{“????“};?????????//“pwd“?command?does?not?have?offset
????int?iDigit=0;??????????????????????????//to?record?the?command‘s?number?of?character
????int?irecordNumber?=?0;?????????????????//to?record?which?record?“history?-[num]“?wants?to?look?for
????int?iNumber?=?0;?????//?which?command?was?executed??0?means?“exit?“;1?means?“cd?“....
????int?iTotal_execution?=?0;?//to?record?how?many?commands?were?executed.
????struct?commandHistory?*?head?=?NULL;??//use?a?chain?to?record?command?history
????struct?savePath?*?head_path?=?NULL;
????char?*strCommand_extract_cd?=?NULL;
????char?*strCommand_extract_history?=?NULL;
????char?*strCommand_extract_path?=?NULL;
????
????char?*token=NULL;
????
????int?iNumber_path?=?0;
????char?buf[80];
????while?（1）
????{
????????char?str1[100]=“+?“;
????????char?str2[100]=“-?“;
????????char?*pathDirectory?=?NULL;
????????printf（“\n$“）;
????????strUser_command1?=?（char?*）malloc（100?*sizeof（char））;
????????fgets（strUser_command1100stdin）;
????????strcpy（strUser_command?strUser_command1）;
????????
????????iDigit?=?（（int）strlen（strUser_command））-1;
????????//printf（“\n%d---digit“iDigit）;
????????strUser_command[iDigit]=‘\0‘;
????????free（strUser_command1）;
????????//if?（head_path!=NULL）
????????//{
????????
????????if（strUser_command[0]==‘/‘||（strUser_command[0]==‘.‘&&strUser_command[1]==‘/‘））?//if?the?input?is?a
????????{
????????????int?status;
????????????status?=?execu_tion（strUser_command）;
?????