When I attempt to run the code that will be provided below, it gives me the following error: Unhandled exception thrown: write access violation. $**$card$**$ was nullptr.

Can you fix my code to make it function as it needs to$?$

Here's the code:

#include

#include

#include

#include

#include

using namespace std;

$//$ Card Node structure

struct CardNode $\{$

string value; $//$ E$.$g$.,"$AS$"$ for Ace of Spades

CardNode$*$ next;

CardNode$($string v$)$ : value$($v$),$ next$($nullptr$)\{\}$

$\}$;

$//$ Deck class

class Deck $\{$

CardNode$*$ top;

public:

Deck$()$ : top$($nullptr$)\{$

initializeDeck$()$;

shuffle$()$;

$\}$

void initializeDeck$()\{$

const string suits $="$CDHS$"$; $//$ Clubs, Diamonds, Hearts, Spades

const string values$[]=\{"2","3","4","5","6","7","8","9","10","$J$","$Q$","$K$","$A$"\}$;

for $($char suit : suits$)\{$

for $($const string& value : values$)\{$

string card $=$ value $+$ suit;

CardNode$*$ newCard $=$ new CardNode$($card$)$;

newCard$->$next $=$ top;

top $=$ newCard;

$\}$

$\}$

$\}$

void shuffle$()\{$

$//$ Shuffle logic: convert to array, shuffle, convert back to linked list

vector cards;

CardNode$*$ current $=$ top;

while $($current$)\{$

cards.push$\_$back$($current$)$;

current $=$ current$->$next;

$\}$

srand$($time$(0))$;

for $($int i $=0$; i $<$ cards.size$()$; $++$i$)\{$

int j $=$ rand$()\%$ cards.size$()$;

swap$($cards$[$i$],$ cards$[$j$])$;

$\}$

top $=$ cards$[0]$;

current $=$ top;

for $($int i $=1$; i $<$ cards.size$()$; $++$i$)\{$

current$->$next $=$ cards$[$i$]$;

current $=$ current$->$next;

$\}$

current$->$next $=$ nullptr;

$\}$

CardNode$*$ drawCard$()\{$

if $(!$top$)$ return nullptr;

CardNode$*$ drawnCard $=$ top;

top $=$ top$->$next;

drawnCard$->$next $=$ nullptr;

return drawnCard;

$\}$

$\}$;

$//$ Player class

class Player $\{$

CardNode$*$ hand;

public:

Player$()$ : hand$($nullptr$)\{\}$

void addCard$($CardNode$*$ card$)\{$

if $(!$hand$)\{$

hand $=$ card;

$\}$

else $\{$

card$->$next $=$ hand;

hand $=$ card;

$\}$

$\}$

void discardCard$($CardNode$*$& river$)\{$

if $(!$hand$)$ return;

CardNode$*$ discard $=$ hand;

hand $=$ hand$->$next;

discard$->$next $=$ river;

river $=$ discard;

$\}$

int calculateScore$()\{$

int score $=0$;

CardNode$*$ current $=$ hand;

while $($current$)\{$

score $+=$ getCardValue$($current$->$value$)$;

current $=$ current$->$next;

$\}$

return score;

$\}$

private:

int getCardValue$($string card$)\{$

if $($card$[0]==\text{'}$A$\text{'})$ return $15$;

if $($card$[0]==\text{'}$K$\text{'}||$ card$[0]==\text{'}$Q$\text{'}||$ card$[0]==\text{'}$J$\text{'}||$ card$[0]==\text{'}1\text{'})$ return $10$;

return $5$;

$\}$

$\}$;

$//$ Game class

class Game $\{$

Deck deck;

Player player$1,$ player$2$;

CardNode$*$ river;

public:

Game$()$ : river$($nullptr$)\{$

dealInitialCards$()$;

$\}$

void dealInitialCards$()\{$

for $($int i $=0$; i $<7$; $++$i$)\{$

player$1.$addCard$($deck$.$drawCard$())$;

player$2.$addCard$($deck$.$drawCard$())$;

$\}$

$\}$

void playRound$()\{$

$//$ Basic round implementation

while $($true$)\{$

takeTurn$($player$1)$;

if $($checkWin$($player$1))$ break;

takeTurn$($player$2)$;

if $($checkWin$($player$2))$ break;

$\}$

determineWinner$()$;

$\}$

private:

void takeTurn$($Player& player$)\{$

player.addCard$($deck$.$drawCard$())$;

player.discardCard$($river$)$;

$\}$

bool checkWin$($Player& player$)\{$

return player.calculateScore$()>=500$;

$\}$

void determineWinner$()\{$

int score$1=$ player$1.$calculateScore$()$;

int score$2=$ player$2.$calculateScore$()$;

if $($score$1>$ score$2)$ cout $<<$ "Player $1$ wins with $"<<$ score$1<<"$ points!

$"$;

else cout $<<$ "Player $2$ wins with $"<<$ score$2<<"$ points!

$"$;

$\}$

$\}$;

int main$()\{$

Game rupeeGame;

rupeeGame.playRound$()$;

return $0$;

$\}$