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As a dynamic list
will implement the Queue, we won't check the 'queue overflow' condition
here. Here, we have two pointers -- front and rear, pointing to
beginning and end of the Queue. When 'front' and 'rear' both point to
NULL, Queue is empty. Every time we add an element to the queue, the
'rear' pointer shifts forward to point to that newly added element.
Check out the algo... Algorithm:-
Step-1:
Create the new node
Step-2: If the Queue is empty go to step-3; or else go to step-4
Step-3: Make the 'front', 'rear' and 'queue' pointers to point to
it. Quit.
Step-4: Add it to the end of the queue. Shift 'rear' pointer to
point to this newly added element. Quit.
C implementation:-
struct node
{
int value;
struct node *next;
}
struct node *queue, *front, *rear;
main( )
{
queue = front = rear = NULL; /*queue
is initially empty*/
..
..
insert(new_value);
..
insert(new_value);
..
}
insert(int value)
{
struct node *new;
new = (struct node *)malloc(sizeof(node));
new->value = value;
new->next = NULL;
if(front == NULL)
{
queue = new;
front = rear = queue;
}
else
{
rear->next = new;
rear = new;
}
}
Related Operations:
Queues
- Concepts
Array implementation - add( ) and delete(
)
Linked List implementation - add( )
and delete( )
Circular queues - add( ) and delete(
)
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