Complete a partial C++ program that uses Priority Queue ADT in which the internal representation of the priority queue are double-linked series of dynamically allocated nodes. The priority queue stores text messages read from an input file by the main{} function. The message and priority info will be stored within an object of the type Message. The text message is stored as a string attribute, and the message priority is represented with an attribute with type Priorities, an enumerated type provided.

If the priority queue contain messages which have different priority levels then the highest priority messages must be removed from the front of the priority queue before any lower priority messages are removed whenever the Dequeue{} method is invoked.

Given two messages of same priority, the message that has been in priority queue the longest has highest priority.

Need messages.cpp and priorityq.cpp

**********messages.h**********

#ifndef MESSAGE_H #define MESSAGE_H

#include using namespace std;

// // Define enumerated Priorities type // enum Priorities {UNKNOWN, LOW, MEDIUM, HIGH};

// // Message class declaration // class Message // Models a single message with priority { private: Priorities priority; // Stores message priority string message; // Stores message contents int uid; // Stores message unique identifier public: /********** Start of functions you must implement for Message **************/ // Implement the following five public functions in the file named message.cpp Message(); // Initializes message to empty string with UNKNOWN priority

void SetPriority(Priorities p); // Sets priority equal to p

void SetMessage(string msg); // Sets message equal to msg

void SetUID(int messageid); // Sets uid to equal messageid. Assumes uid will be unique. Priorities GetPriority() const; // Returns priority value without modification

string GetMessage() const; // Returns message contents without modification

int GetUID() const; // Returns uid value without modification /*********** End of functions you must implement for Message ***************/ void Print() const // DO NOT MODIFY OR RELOCATE THIS FUNCTION { cout << "[";

cout << uid << ", "; if (priority == HIGH) cout << "H"; else if (priority == MEDIUM) cout << "M"; else if (priority == LOW) cout << "L"; else cout << "U"; cout << ", " << message << "]"; } // End Print() const };

#endif

**********priorityq.h**********

#ifndef PRIORITYQ_H #define PRIORITYQ_H

#include #include "message.h" using namespace std;

// // Exception classes for PriorityQ // class EmptyPQ { /* No additional code */ }; // Exception class for empty PriorityQ condition

class FullPQ { /* No additional code */ }; // Exception class for full PriorityQ condition

class InvalidPeekPQ { /* No additional code */ }; // Exception class for invalid PriorityQ peek condition

class InvalidUIDPQ { /* No additional code */ }; // Exception class for invalid PriorityQ UID search

// // Priority Queue Node Structure // struct Node // Linked priority queue node structure { Message data; // Field for storing data in the priority queue node Node* nextPtr; // Points to next priority queue node (points from front towards rear) Node* previousPtr; // Points to previous priority queue node (points from rear towards front) };

// // PriorityQ class declaration // class PriorityQ // Double linked queue of messages sorted by priority { private: Node* frontPtr; // Points to front node of priority queue Node* rearPtr; // Points to rear node of priority queue int count; // Number of values stored in priority queue public: /********** Start of functions you must implement for PriorityQ **************/ // Implement the following nine public functions in the file named priorityq.cpp PriorityQ(); // PriorityQ() // Initializes all private variables to indicate an empty priority queue ~PriorityQ(); //~PriorityQ() // Deallocates all priority queue nodes // No memory leak allowed void MakeEmpty(); // MakeEmpty() // Deallocates all priority queue nodes and returns priority queue to empty ready-to-use state // No memory leak allowed void Enqueue(Message msg); // Enqueue() // Adds value to priority queue in correct position and increments count. // Duplicates are allowed. // Highest priority messages must always be at front of queue // Lowest priority messages must always be at rear of queue // Add AFTER messages of similar priority // If queue is already full, throws FullPQ exception.

void Dequeue(); // Dequeue() // Removes highest priority message from front of priority queue and decrements count. // If queue is empty, throws EmptyPQ exception // No memory leak allowed

void Purge(Priorities p); // Purge() // Removes all messages of priority p from queue leaving all other messages in priority queue // If queue is empty, throws EmptyPQ exception // No memory leak allowed Message Front() const; // Front() // Returns message at front of priority queue. DOES NOT MODIFY THE PRIORITY QUEUE // If queue is empty, throws EmptyPQ

Message Rear() const; // Rear() // Returns message at rear of priority queue. DOES NOT MODIFY THE PRIORITY QUEUE // If queue is empty, throws EmptyPQ

Message Peek(int n) const; // Peek() // Returns message n positions from front of priority queue. DOES NOT MODIFY THE PRIORITY QUEUE // If position n does not exist, throws InvalidPeekPQ bool IsFull() const; // IsFull() // Returns true if queue is full. Returns false otherwise. DOES NOT MODIFY THE PRIORITY QUEUE bool IsEmpty() const; // IsEmpty() // Returns true if queue is empty. Returns false otherwise. DOES NOT MODIFY THE PRIORITY QUEUE int Size() const; // Size() // Returns number of items stored in priority queue. DOES NOT MODIFY THE PRIORITY QUEUE

Message IsPresent(int uid) const; // IsPresent() // Returns message with uid if it is present in PriorityQ. DOES NOT MODIFY THE PRIORITY QUEUE // If message with specified uid does not exist, throws InvalidUIDPQ

/*********** End of functions you must implement for PriorityQ ***************/ void Print() const // Print() -- DO NOT MODIFY OR RELOCATE THIS FUNCTION // Prints contents of priority queue without modifying its contents { Node* tempPtr = frontPtr;

// Prints queue nodes Front-to-Rear order cout << "Front { "; while (tempPtr != NULL) { //cout << '(' << tempPtr->data.GetMessage() << ')' << ' '; tempPtr->data.Print(); cout << ' '; tempPtr = tempPtr->nextPtr; } cout << "} Rear Rear { ";

// Prints queue nodes Rear-to-Front order tempPtr = rearPtr; while (tempPtr != NULL) { //cout << '(' << tempPtr->data.GetMessage() << ')' << ' '; tempPtr->data.Print(); cout << ' '; tempPtr = tempPtr->previousPtr; } cout << "} Front"; } // End Print() };

#endif