Write a program of link list
implementation of a queue.
#include <stdio.h>
#include<alloc.h>
#include<conio.h>
struct node
{
int data ;
struct node *link ;
} ;
struct queue
{
struct node *front ;
struct node *rear ;
} ;
void initqueue ( struct queue * )
;
void addq ( struct queue *, int )
;
int delq ( struct queue * ) ;
void delqueue ( struct queue * )
;
main( )
{
struct queue a ;
int i ;
initqueue ( &a ) ;
addq ( &a, 11 ) ;
addq ( &a, -8 ) ;
addq ( &a, 23 ) ;
addq ( &a, 19 ) ;
addq ( &a, 15 ) ;
addq ( &a, 16 ) ;
addq ( &a, 28 ) ;
i = delq ( &a ) ;
printf ( "\nItem extracted:
%d", i ) ;
i = delq ( &a ) ;
printf ( "\nItem extracted:
%d", i ) ;
i = delq ( &a ) ;
printf ( "\nItem extracted:
%d", i ) ;
delqueue ( &a ) ;
}
void initqueue ( struct queue *q
)
{
q -> front = q -> rear =
NULL ;
}
void addq ( struct queue *q, int
item )
{
struct node *temp ;
temp = ( struct node * ) malloc (
sizeof ( struct node ) ) ;
if ( temp == NULL )
printf ( "\nQueue is
full." ) ;
temp -> data = item ;
temp -> link = NULL ;
if ( q -> front == NULL )
{
q -> rear = q -> front =
temp ;
return ;
}
q -> rear -> link = temp ;
q -> rear = q -> rear ->
link ;
}
int delq ( struct queue * q )
{
struct node *temp ;
int item ;
if ( q -> front == NULL )
{
printf ( "\nQueue is
empty." ) ;
return NULL ;
}
item = q -> front -> data ;
temp = q -> front ;
q -> front = q -> front
-> link ;
free ( temp ) ;
return item ;
}
void delqueue ( struct queue *q )
{
struct node *temp ;
if ( q -> front == NULL )
return ;
while ( q -> front != NULL )
{
temp = q -> front ;
q -> front = q -> front
-> link ;
free ( temp ) ;
}
}
Output
