Write the implementation file, priority_queue.c, for the interface in the given header file, priority_queue.h. Turn in your priority_queue.c file and a suitable main program, main.c, that tests the opaque object. priority_queue.h is attached as a file to this assignment but is also listed here for your convenience. Your implementation file should implement the priority queue using a heap data structure. Submissions that implement the priority queue without using a heap will not receive any credit.

#ifndef PRIORITY_QUEUE_H

#define PRIORITY_QUEUE_H

enum status { FAILURE, SUCCESS };

typedef enum status Status;

enum boolean { FALSE, TRUE };

typedef enum boolean Boolean;

typedef void* PRIORITY_QUEUE;

//Precondition: Creates an empty priority queue that can store integer data items // with different integer priority. Higher // integer values indicate higher priority in the queue. For example, consider the // priority and the data value to be key-value pairs where the priority is the key // and the data is the value. The queue could hold 21,10 and 35, 5 so that the // first item to be removed from the queue would be the data value 5 because // it has higher priority (35) than the data value 10 which only has (21). //Postcondition: Returns the handle to an empty priority queue.

PRIORITY_QUEUE priority_queue_init_default(void);

//Precondition: hQueue is a handle to a valid priority queue opaque object. // Higher priority_level values indicate higher priority in the queue. // data_item is simply a value we are storing in the queue.

//Postcondition: returns SUCCESS if the item was successfully added to the queue // and FAILURE otherwise.

Status priority_queue_insert(PRIORITY_QUEUE hQueue, int priority_level, int data_item);

//Precondition: hQueue is a handle to a valid priority queue opaque object.

//Postcondition: returns SUCCESS if the highest priority item was removed from the queue // and FAILURE if the queue was empty.

Status priority_queue_service(PRIORITY_QUEUE hQueue);

//Precondition: hQueue is a handle to a valid priority queue opaque object.

//Postcondition: returns a copy of the data value for the // highest priority item in the queue. Sets status to SUCCESS if there is // at least one item in the queue and FAILURE otherwise. If status is // passed in as NULL then the status value is ignored for this run of the // function.

int priority_queue_front(PRIORITY_QUEUE hQueue, Status& status);

//Precondition: hQueue is a handle to a valid priority queue opaque object.

//Postcondition: returns TRUE if the priority_queue is empty and FALSE otherwise.

Boolean priority_queue_is_empty(PRIORITY_QUEUE hQueue);

//Precondition: phQueue is a pointer to the handle of a valid priority queue opaque object. //Postcondition: The opaque object will be free'd from memory and the handle pointed to // by phQueue will be set to NULL.

void priority_queue_destroy(PRIORITY_QUEUE* phQueue); #endif