C Program to implement Deque using circular array

By | 11.04.2017

Implement Deque using circular array


Write a C Program to implement Deque using circular array. Here’s simple Program to implement Deque using circular array in C Programming Language.


What is Queue ?


Queue is also an abstract data type or a linear data structure, in which the first element is inserted from one end called REAR, and the deletion of existing element takes place from the other end called as FRONT.

This makes queue as FIFO data structure, which means that element inserted first will also be removed first.


Basic Operations : :


  • enqueue() − add (store) an item to the queue.
  • dequeue() − remove (access) an item from the queue.
  • peek() − Gets the element at the front of the queue without removing it.
  • isfull() − Checks if the queue is full.
  • isempty() − Checks if the queue is empty.

Below is the source code for C Program to implement Deque using circular array which is successfully compiled and run on Windows System to produce desired output as shown below :


SOURCE CODE : :


/*  C Program to implement Deque using circular array  */

#include<stdio.h>
#include<stdlib.h>
#define MAX 7

int deque_arr[MAX];
int front=-1;
int rear=-1;

void insert_frontEnd(int item);
void insert_rearEnd(int item);
int delete_frontEnd();
int delete_rearEnd();
void display();
int isEmpty();
int isFull();

int main()
{
        int choice,item;
        while(1)
        {
                printf("\n\n1.Insert at the front end\n");
                printf("2.Insert at the rear end\n");
                printf("3.Delete from front end\n");
                printf("4.Delete from rear end\n");
                printf("5.Display\n");
                printf("6.Quit\n");
                printf("\nEnter your choice : ");
                scanf("%d",&choice);

                switch(choice)
                {
                case 1:
                        printf("\nInput the element for adding in queue : ");
                        scanf("%d",&item);
                        insert_frontEnd(item);
                        break;
                case 2:
                        printf("\nInput the element for adding in queue : ");
                        scanf("%d",&item);
                        insert_rearEnd(item);
                        break;
                 case 3:
                        printf("\nElement deleted from front end is : %d\n",delete_frontEnd());
                        break;
                 case 4:
                        printf("\nElement deleted from rear end is : %d\n",delete_rearEnd());
                        break;
                 case 5:
                        display();
                        break;
                 case 6:
                        exit(1);
                 default:
                        printf("\nWrong choice\n");
                }/*End of switch*/
                printf("\nfront = %d, rear =%d\n", front , rear);
                display();
        }/*End of while*/
}/*End of main()*/

void insert_frontEnd(int item)
{
        if( isFull() )
        {
                printf("\nQueue Overflow\n");
                return;
        }
        if( front==-1 )/*If queue is initially empty*/
        {
                front=0;
                rear=0;
        }
        else if(front==0)
                front=MAX-1;
        else
                front=front-1;
        deque_arr[front]=item ;
}/*End of insert_frontEnd()*/

void insert_rearEnd(int item)
{
        if( isFull() )
        {
                printf("\nQueue Overflow\n");
                return;
        }
        if(front==-1)  /*if queue is initially empty*/
        {
                front=0;
                rear=0;
        }
        else if(rear==MAX-1)  /*rear is at last position of queue */
                rear=0;
        else
                rear=rear+1;
        deque_arr[rear]=item ;
}/*End of insert_rearEnd()*/

int delete_frontEnd()
{
        int item;
        if( isEmpty() )
        {
                printf("\nQueue Underflow\n");
                exit(1);
        }
        item=deque_arr[front];
        if(front==rear) /*Queue has only one element */
        {
                front=-1;
                rear=-1;
        }
        else
                if(front==MAX-1)
                        front=0;
                else
                        front=front+1;
        return item;
}/*End of delete_frontEnd()*/

int delete_rearEnd()
{
        int item;
        if( isEmpty() )
        {
                printf("\nQueue Underflow\n");
                exit(1);
        }
        item=deque_arr[rear];

        if(front==rear) /*queue has only one element*/
        {
                front=-1;
                rear=-1;
        }
        else if(rear==0)
                rear=MAX-1;
        else
                rear=rear-1;
        return item;
}/*End of delete_rearEnd() */

int isFull()
{
        if ( (front==0 && rear==MAX-1) || (front==rear+1) )
                return 1;
        else
                return 0;
}/*End of isFull()*/

int isEmpty()
{
        if( front == -1)
                return 1;
        else
                return 0;
}/*End of isEmpty()*/

void display()
{
        int i;
        if( isEmpty() )
        {
                printf("\nQueue is empty\n");
                return;
        }
        printf("\nQueue elements :\n");
        i=front;
        if( front<=rear )
        {
                while(i<=rear)
                        printf("%d ",deque_arr[i++]);
        }
        else
        {
                while(i<=MAX-1)
                        printf("%d ",deque_arr[i++]);
                i=0;
                while(i<=rear)
                        printf("%d ",deque_arr[i++]);
        }
        printf("\n");
}/*End of display() */

OUTPUT : :


/*  C Program to implement Deque using circular array  */

1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 1

Input the element for adding in queue : 1

front = 0, rear =0

Queue elements :
1


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 2

Input the element for adding in queue : 2

front = 0, rear =1

Queue elements :
1 2


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 1

Input the element for adding in queue : 3

front = 6, rear =1

Queue elements :
3 1 2


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 2

Input the element for adding in queue : 4

front = 6, rear =2

Queue elements :
3 1 2 4


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 1

Input the element for adding in queue : 5

front = 5, rear =2

Queue elements :
5 3 1 2 4


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 2

Input the element for adding in queue : 6

front = 5, rear =3

Queue elements :
5 3 1 2 4 6


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 3

Element deleted from front end is : 5

front = 6, rear =3

Queue elements :
3 1 2 4 6


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 4

Element deleted from rear end is : 6

front = 6, rear =2

Queue elements :
3 1 2 4


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 5

Queue elements :
3 1 2 4

front = 6, rear =2

Queue elements :
3 1 2 4


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 3

Element deleted from front end is : 3

front = 0, rear =2

Queue elements :
1 2 4


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 4

Element deleted from rear end is : 4

front = 0, rear =1

Queue elements :
1 2


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 3

Element deleted from front end is : 1

front = 1, rear =1

Queue elements :
2


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 4

Element deleted from rear end is : 2

front = -1, rear =-1

Queue is empty


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 5

Queue is empty

front = -1, rear =-1

Queue is empty


1.Insert at the front end
2.Insert at the rear end
3.Delete from front end
4.Delete from rear end
5.Display
6.Quit

Enter your choice : 6

Process returned 1

If you found any error or any queries related to the above program or any questions or reviews , you wanna to ask from us ,you may Contact Us through our contact Page or you can also comment below in the comment section.We will try our best to reach up to you in short interval.


Thanks for reading the post….

3.5 4 votes
Article Rating
Subscribe
Notify of
guest
1 Comment
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
budgam

Thanks! A clean code snippet