Assuming that you have the following base code already implemented, write a C$++$ program to find the sum of all elements of a queue.

#include

#include

using namespace std;

const int MAX$\_$SIZE $=100$;

class Queue $\{$

private:

int front; $//$ Front index of the queue

int rear; $//$ Rear index of the queue

int arr$[$MAX$\_$SIZE$]$; $//$ Array to store elements

public:

Queue$()\{$

front $=-1$; $//$ Initialize front index to $-1$

rear $=-1$; $//$ Initialize rear index to $-1$

$\}$

bool isFull$()\{$

return $($rear $==$ MAX$\_$SIZE $-1)$; $//$ Check if the queue is full

$\}$

bool isEmpty$()\{$

return $($front $==-1$ && rear $==-1)$; $//$ Check if the queue is empty

$\}$

void enqueue$($int x$)\{$

if $($isFull$())\{$

$//$ Display error message if queue is full

cout $<<$ "Error: Queue is full" $<<$ endl;

return;

$\}$

if $($isEmpty$())\{$

front $=0$;

rear $=0$;

$\}$ else $\{$

rear$++$;

$\}$

arr$[$rear$]=$ x; $//$ Insert the element at the rear index

$\}$

void dequeue$()\{$

if $($isEmpty$())\{$

cout $<<$ "Error: Queue is empty" $<<$ endl; $//$ Display error message if queue is empty

return;

$\}$

if $($front $==$ rear$)\{$

front $=-1$;

rear $=-1$;

$\}$ else $\{$

front$++$;

$\}$

$\}$

int peek$()\{$

if $($isEmpty$())\{$

cout $<<$ "Error: Queue is empty" $<<$ endl; $//$ Display error message if queue is empty

return $-1$;

$\}$

return arr$[$front$]$; $//$ Return the element at the front of the queue

$\}$

void display$()\{$

if $($isEmpty$())\{$

cout $<<$ "Error: Queue is empty" $<<$ endl; $//$ Display error message if queue is empty

return;

$\}$

cout $<<$ "Queue elements are: $"$;

for $($int i $=$ front; i $<=$ rear; i$++)\{$

cout $<<$ arr$[$i$]<<""$; $//$ Display all elements in the queue

$\}$

cout $<<$ endl;

$\}$

$//$ Function to calculate the sum of all elements in the queue

int sum$\_$Queue$($Queue & q$)$

$//$Enter your code here:

$\}$

$\}$;