Implement Circular Queue in C using arrays that performs following operations. (a) INSERT (b) DELETE (c) DISPLAY.

 #include <stdio.h>

#include <stdlib.h>

#define max 6

int queue[max];

int front = -1;

int rear = -1;

//insert element

void enqueue(int element)

{

    if (front == -1 && rear == -1) //empty

    {

        front = 0;

        rear = 0;

        queue[rear] = element;

    }

    else if ((rear + 1) % max == front) // full

    {

        printf("Queue is overflow..");

    }

    else

    {

        rear = (rear + 1) % max; // rear is incremented

        queue[rear] = element;   // assigning a value to the queue at the rear position.

    }

}

int dequeue()

{

    if ((front == -1) && (rear == -1)) // condition to check queue is empty

    {

        printf("\nQueue is underflow..");

    }

    else if (front == rear)

    {

        printf("\nThe dequeued element is %d", queue[front]);

        front = -1;

        rear = -1;

    }

    else

    {

        printf("\nThe dequeued element is %d", queue[front]);

        front = (front + 1) % max;

    }

}

// function to display the elements of a queue

void display()

{

    int i = front;

    if (front == -1 && rear == -1)

    {

        printf("\n Queue is empty..");

    }

    else if( front < rear)

    {

        printf("\nElements in a Queue are :");

        for(i=front;i<=rear;i++)

            {

                printf("%d,", queue[i]);

            }

    }

    else{

             for(i=front;i<=5;i++)

            {

                printf("%d,", queue[i]);

            }

            for(i=0;i<=rear;i++)

            {

                printf("%d,", queue[i]);

            }

    }

}

int main()

{

    int choice = 1, x; // variables declaration

    while (choice < 4 && choice != 0) // while loop

    {

        printf("\n Press 1: Insert an element");

        printf("\nPress 2: Delete an element");

        printf("\nPress 3: Display the element");

        printf("\nEnter your choice");

        scanf("%d", &choice);

        switch (choice)

        {

        case 1:

            printf("Enter the element which is to be inserted");

            scanf("%d", &x);

            enqueue(x);

            break;

        case 2:

            dequeue();

            break;

        case 3:

            display();

        }

    }

    return 0;

}