in c$++$

Here are the new requirements

Variables in this shell will be identifiers that begin with the $ character but otherwise follow the usual convention where you should use upper and lower case letters or digits

Variables will only store strings and they are defined upon first use.

They are set using the set command which has the syntax SET $=$

The contents of a variable are displayed using the echo command: echo

It is possible to use a variable in any of the other commands.

Update your tokenizer to scan and parse these new features. Use a dictionary for a symbol table for variables with name and current value as entries. Print the symbol table whenever a parse has been completed.

the code:

#include

#include

#include

#define MAX$\_$TOKENS $100$

#define MAX$\_$TOKEN$\_$LENGTH $100$

$//$ Function to tokenize the command string

char$**$ tokenize$($const char$*$ command, int$*$ token$\_$count$)\{$

$$ char$**$ tokens $=$ malloc$($MAX$\_$TOKENS $*$ sizeof$($char$*))$;

$$ if $(!$tokens$)\{$

$$ perror$("$Failed to allocate memory"$)$;

$$ exit$($EXIT$\_$FAILURE$)$;

$\}$

$$ char$*$ command$\_$copy $=$ strdup$($command$)$;

$$ if $(!$command$\_$copy$)\{$

$$ perror$("$Failed to duplicate command"$)$;

$$ free$($tokens$)$;

$$ exit$($EXIT$\_$FAILURE$)$;

$\}$

$$ const char$*$ delimiters $="\backslash$t

$"$; $//$ Delimiters: space, tab, newline

$$ char$*$ token $=$ strtok$($command$\_$copy, delimiters$)$;

$*$token$\_$count $=0$;

$$ while $($token $!=$ NULL && $*$token$\_$count $<$ MAX$\_$TOKENS$)\{$

$$ tokens$[*$token$\_$count$]=$ strdup$($token$)$;

$$ if $(!$tokens$[*$token$\_$count$])\{$

$$ perror$("$Failed to allocate memory for token"$)$;

$//$ Free up previously allocated tokens

for $($int i $=0$; i $<*$token$\_$count; i$++)\{$

$$ free$($tokens$[$i$])$;

$\}$

$$ free$($tokens$)$;

$$ free$($command$\_$copy$)$;

$$ exit$($EXIT$\_$FAILURE$)$;

$\}$

$(*$token$\_$count$)++$;

$$ token $=$ strtok$($NULL$,$ delimiters$)$;

$\}$

$$ free$($command$\_$copy$)$;

$$ return tokens;

$\}$

$//$ Function to free the allocated tokens

void free$\_$tokens$($char$**$ tokens, int token$\_$count$)\{$

$$ for $($int i $=0$; i $<$ token$\_$count; i$++)\{$

$$ free$($tokens$[$i$])$;

$\}$

$$ free$($tokens$)$;

$\}$

int main$()\{$

$$ const char$*$ command $="$ls $-$l $/$home$/$user$/$docs$"$;

$$ int token$\_$count $=0$;

char$**$ tokens $=$ tokenize$($command$,$ &token$\_$count$)$;

$$ printf$("$Tokens:

$")$;

$$ for $($int i $=0$; i $<$ token$\_$count; i$++)\{$

$$ printf$("\%$s

$",$ tokens$[$i$])$;

$\}$

$$ free$\_$tokens$($tokens$,$ token$\_$count$)$;

$$ return $0$;

$\}$