/* HW5
 * Due: 22 October 2017
 * Problem Header Hash Code: bfd416aa02529df87ee21caadec5ab81
*/
package hw5;

public class Queue {
    Node[] arr; // circular Queue
    int capacity;
    int front;
    int back;
    int size;

    public Queue(int cap){
        arr = new Node[cap];
        capacity = cap;
    }

    public void enqueue(Node node){
        if (!isFull()){
            if(back < capacity-1){
                arr[back] = node;
                back++;
            }else{
                back = 0;
                arr[back] = node;
            }size++;
        }else{
            System.out.println("Queue Overflow!!!");
        }
    }

    public Node dequeue(){
        if (!isEmpty()){
            Node keep = arr[front];
            while(arr[front]==null){
              front++;
            }
              arr[front] = null;
              front++;
              //if(front==capacity) front=0;
              size--;
              return keep;
        }else{
            System.out.println("Queue Underflow!!!");
            return null;
        }
    }

    public boolean isEmpty(){
        boolean check = false;
        if(size == 0){
            check = true;
        }
        return check;
    }

    public boolean isFull(){
        boolean check2 = false;
        if(size == capacity){
            check2 = true;
        }
        return check2;
    }

    public void printCircularIndices(){
        System.out.println("Front index = " + front + " Back index = " + back);
    }

    public void printQueue(){
        if (!isEmpty()){
            System.out.print("[Front] ");
            if(back>front){
                for(int i=front;i<back;i++){
                    System.out.print(arr[i].data);
                }
            }else{
                for(int i=0;i<front;i++){
                    System.out.print(arr[i].data);
                }for(int i=back;i<capacity;i++){
                    System.out.print(arr[i].data);
                }
            }
            System.out.println("[Back]");
        }else{
            System.out.println("Empty Queue!!!");
        }

    }
}