1. set global variables front and rear = -1 and declare max for storing the size
2. Display the menu of queue operations to the user
    b. Read the user's selection and perform the corresponding operation:
        - If user selects enque, call enque( )
        - If user selects dequeue, call dequeue()
        - If user selects display, call display()
        - If user selects Exit, terminate the program
3. in enque function 
	if (front == 0 && rear == max -1) || front == ++rear
	   print "stack overflow"
	   exit
	if (front == -1)
	   set front and rear to 0
	else if (rear == max - 1)
	   rear = 0;
	else
	    rear = ++rear;
	Q[rear] = item;
	
4. in dequeue function
	if front == -1
	    print "queue underflow"
	    exit
	item = queue[front]
	
	if front == rear
	    set front and rear to -1
	if front == max - 1
	    front++

5. in display function
	if top == -1
	    print "empty stack"
	else 
	    print element elements of queue from front to rear
6. repeats above steps untill user chose to terminate or program terminate automatically by stackoverflow or underflow condition

--------------------------------------------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>

int rear = -1, front = -1, max;

void enqueue(int value, int queue[]);
void dequeue(int queue[]);
void display(int queue[]);

int main()
{
    int selection, value;
    printf("Enter size of the queue: ");
    scanf("%d", &max);
    int queue[max];

    while (1) {
        printf("\nSelect operation to perform on stack\n");
        printf("1. Enqueue\n2. Dequeue\n3. Display\n4. Exit\n");
        printf(" : ");
        scanf("%d", &selection);

        switch (selection) {
            case 1:
                printf("Enter the value to enqueue: ");
                scanf("%d", &value);
                enqueue(value, queue);
                break;
            case 2:
                dequeue(queue);
                break;
            case 3:
                display(queue);
                break;
            case 4:
                return 0;
            default:
                printf("Invalid choice. Please try again.\n");
        }
    }
}

void enqueue(int value, int queue[])
{
    if ((front == 0 && rear == max -1) || (front == rear + 1)){
        printf("\nQueue Overflow\n");
        exit(0);
    }
    if (front == -1){
        front = 0;
        rear = 0;
    }
    else if (rear == max - 1){
        rear = 0;
    }
    else {
        rear++;
    }
    queue[rear] = value;
}

void dequeue(int queue[]){
    if (front == -1){
        printf("\nQueue Underflow\n");
        exit(0);
    }
    int value = queue[front];

    if (front == rear){
        front = 0;
        rear = 0;
    }
    if (front == max -1){
        front++;
    }
    printf("%d has been deleted\n", value);
}

void display(int queue[])
{
    if (front == -1)
    {
        printf("\nQueue is empty\n");
        exit(0);
    }
    if (front <= rear){
        for (int i = front; i <= rear; i++){
            printf("%d ",queue[i]);
        }
    }
    else {
        for (int i = front; i < max; i++){
            printf("%d ",queue[i]);
        }
        for (int i = 0; i <= rear; i++){
            printf("%d ",queue[i]);
        }
    }
}