Write C++ code with comments an update function that updates the queue whenever the priority changes. I have this priority queue class.

#include

#include

#include

#include

#include "Library.h"

using namespace std;

// Node declaration and properties

struct node {

int priority;

int data;

struct node *link;

};

// Class implementing the priority queue

class PQ {

private:

node *front;

public:

PQ() {

front = NULL;

}

// Push function for PQ

void push(int data, int priority) {

node *demo, *q;

demo = new node;

demo->data = data;

demo->priority = priority;

if (front == NULL || priority < front->priority) {

demo->link = front;

front = demo;

}

else {

q = front;

while (q->link != NULL && q->link->priority <= priority)

q = q->link;

demo->link = q->link;

q->link = demo;

}

}

// Method to pop the highest priority element in the queue

void pop() {

node *temp;

if (front == NULL)

cout << "There is no item in the queue." << endl;

else {

temp = front;

front = front->link;

free(temp);

}

}

// Display the elements in the queue

void display() {

node *ptr;

ptr = front;

if (front == NULL)

cout << "Priority Queue is empty" << endl;

else {

cout << "Priority Queue is : " << endl;

cout << "Priority Item" << endl;

while (ptr != NULL) {

cout << ptr->priority << " " << ptr->data << endl;

ptr = ptr->link;

}

}

}

};