public class IsEmpty {

static class Queue{

int maxsize;

int queueArray[];

int front;

int rear;

Queue(int size){

maxsize= size;

queueArray= new int[maxsize];

front= -1;

rear= -1;

}

// insert elements to the queue

void add(int val){

if(rear==maxsize-1){

System.out.println("The queue is full");

return;

}

if(rear==-1){

front= rear= 0;

queueArray[rear]= val;

}

else{

queueArray[++rear]= val;

}

}

// delete element from the queue

void remove(){

if(rear==-1){

System.out.println("The queue is empty");

return;

}

front++;

}

// check if queue is empty or not

boolean isEmpty(){

if(rear==-1){

return true;

}

return false;

}

// display elements of the queue

void display(){

if(rear==-1){

System.out.println("Empty queue");

return;

}

for(int i= front; i<=rear; i++){

System.out.print(queueArray[i] + " ");

}

System.out.println();

}

}

public static void main(String[] args) {

Queue q= new Queue(5);

q.add(1);

q.add(2);

q.add(3);

q.display();

q.remove();

q.add(4);

q.display(); // 1 2 3 4 5

if(q.isEmpty()){

System.out.println("The queue is empty");

}

else{

System.out.println("The queue is not empty");

}

}

}