Please I need help with this assignment. Its priority queue - I'm still learning C and don't understand it a lot. thank you in advance.

COMP1020

Day

8

Daily

Spring

2017

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 empt

y.

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 SUCCES

S 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);

//Preconditi

on: 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);

COMP1020

Day

8

Daily

Spring

2017

//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