Objectives

$$ Review the C programming language.

$$ Learn how to use the Netbeans Integrated Development Environment $($IDE$)$ for C

programs

$$ Implement a Priority Queue using a linked list.

Problem description

You need to implement a Priority Queue using a linked list.

A Priority Queue is used in Operating Systems kernel as part of the scheduling algorithm. Briefly,

when a process cannot continue running $($perhaps because it is waiting for some event such as

input$/$output$),$ the OS has to choose which waiting process that is ready to run gets control of the

CPU. Part of this algorithm involves a priority queue where the ready processes are ordered by their

priority. All things being equal, the highest priority task will be allowed to run.

Template code is given to you. You need to implement the functions PQ$\_$insert and PQ$\_$delete

functions.

You are given the header file pri$\_$queue.h:

#ifndef PRI$\_$QUEUE$\_$H

#define PRI$\_$QUEUE$\_$H

typedef struct node $\{$

int priority;

char $*$ data;

struct node $*$ next;

$\}$ Node$\_$t$,*$ Node$\_$ptr$\_$t;

extern void PQ$\_$insert$($ int, char $*)$;

extern Node$\_$ptr$\_$t PQ$\_$delete$()$;

extern Node$\_$ptr$\_$t PQ$\_$get$\_$head$()$;

extern int PQ$\_$get$\_$size$()$;

#endif $/*$ PRI$\_$QUEUE$\_$H $*/$

This header file defines new data types:

$$ Node$\_$t: A data structure for the nodes in the Priority Queue linked list. Each node contains its

priority, data $($a string$)$ and a pointer to the next node in the list. $($If a node is the last one on the

list its $$next$$ is NULL.$)$