queue programs in c -1

Question 1.Write program that implements queue as an array ?

Ans :

#include 

#include 



#define MAX 10



void addq ( int *, int, int *, int * ) ;

int delq ( int *, int *, int * ) ;



void main( )

{

	int arr[MAX] ;

	int front = -1, rear = -1, i ;



	clrscr( ) ;



	addq ( arr, 23, &front, &rear ) ;

	addq ( arr, 9, &front, &rear ) ;

	addq ( arr, 11, &front, &rear ) ;

	addq ( arr, -10, &front, &rear ) ;

	addq ( arr, 25, &front, &rear ) ;

	addq ( arr, 16, &front, &rear ) ;

	addq ( arr, 17, &front, &rear ) ;

	addq ( arr, 22, &front, &rear ) ;

	addq ( arr, 19, &front, &rear ) ;

	addq ( arr, 30, &front, &rear ) ;

	addq ( arr, 32, &front, &rear ) ;



	i = delq ( arr, &front, &rear ) ;

	printf ( "\nItem deleted: %d", i ) ;



	i = delq ( arr, &front, &rear ) ;

	printf ( "\nItem deleted: %d", i ) ;



	i = delq ( arr, &front, &rear ) ;

	printf ( "\nItem deleted: %d", i ) ;



	getch( ) ;

}



/* adds an element to the queue */

void addq ( int *arr, int item, int *pfront, int *prear  )

{

	if ( *prear == MAX - 1 )

	{

		printf ( "\nQueue is full." ) ;

		return ;

	}



	( *prear )++ ;

	arr[*prear] = item ;



	if ( *pfront == -1 )

		*pfront = 0 ;

}



/* removes an element from the queue */

int delq ( int *arr, int *pfront, int *prear )

{

	int data ;



	if ( *pfront == -1 )

	{

		printf ( "\nQueue is Empty." ) ;

		return NULL ;

	}



	data = arr[*pfront] ;

	arr[*pfront] = 0 ;

	if ( *pfront == *prear )

		 *pfront = *prear = -1 ;

	else

		 ( *pfront )++ ;



	return  data ;

}