Queue_array.java

package DATA_STRUCTURE;
import java.util.Scanner;
public class Queue_array {
    Scanner s = new Scanner(System.in);
    static final int max = 5;               //FIRST IN FIRST OUT FIFO
    int rear = -1;
    int front  = -1;
    int[] Queue = new int[max];


    boolean isFull(){
        if(rear == max-1){
            return true;
        }
        else{
            return false;
        }
    }

    boolean isEmpty(){
        if(rear == -1 || front ==-1){
            return true;
        }
        else {
            return false;
        }
    }


    void insert(){
        if(isFull()){
            System.out.println("Queue is Full..!!");
            return;
        }
        else{
            System.out.println("Enter element");
            int e = s.nextInt();
            rear++;
            Queue[rear] = e;
            if(rear == 0){
                front = 0;
            }
        }


    }

    void Delete(){
        if(isEmpty()){
            System.out.println("Queue is empty");
        }
        else if(front == rear ){
            front = rear = -1;
        }
        else{
            int element = Queue[front];
            front++;
            System.out.println(element+" Deleted from queue");
        }
    }

    void display(){
        for (int i = front; i <= rear ; i++) {
            System.out.print(Queue[i]+" ");
        }
    }

    public static void main(String[] args) {
        Queue_array q = new Queue_array();
        q.insert();
        q.insert();
        q.insert();
        q.insert();
        q.insert();
        q.Delete();
        q.Delete();

        System.out.println("\n\n");
        System.out.print("Front --> ");
        q.display();
        System.out.print(" <--Rear");
        
    
    }
}