Queue implementation using linked list - DS TUTORIAL

demonstrate how to implement queue using linked list.

Description:

The advantage of using linked list is that there is no size limit. The size of queue grow and shrink as per insertion and deletion takes place.

Code:

# include <stdio.h>
# include <stdlib.h>
struct node
{
int data;
struct node *link;
};
void insert(struct node **front, struct node **rear , int value)
{
struct node *temp;
temp=(struct node *)malloc(sizeof(struct node));
 if(temp==NULL)
 {
 printf("No Memory available\n");
 exit(0);
 }
 temp->data = value;
 temp->link=NULL;
 if(*rear == NULL)
 {
 *rear = temp;
 *front = *rear;
 }
 else
 {
 (*rear)->link = temp;
 *rear = temp;
 }
 }

void deleteQ(struct node **front, struct node **rear , int *value)
{
struct node *temp;
if((*front == *rear)  && (*rear == NULL))
{
printf(" The queue is empty can not delete Error\n");
exit(0);
}
 *value = (*front)->data;
 temp = *front;
 *front = (*front)->link;
 if(*rear == temp)
 *rear = (*rear)->link;
 free(temp);
 }

void main()
{
struct node *front=NULL,*rear = NULL;
int n,value;
do
{
  do
  {
   printf("Enter the element to be inserted\n");
   scanf("%d",&value);
   insert(&front,&rear,value);
   printf("Enter 1 to continue\n");
   scanf("%d",&n);
  } while(n == 1);
  printf("Enter 1 to delete an element\n");
  scanf("%d",&n);
  while( n == 1)
 {
  deleteQ(&front,&rear,&value);
  printf("The value deleted is %d\n",value);
  printf("Enter 1 to delete an element\n");
  scanf("%d",&n);
 }
   printf("Enter 1 to continue\n");
   scanf("%d",&n);
 } while(n == 1);
}

Output