/*
	Demonstration of Queue
	
	
	author: 
	course: 15-111 Java Programming 
	section: 
	date: 	

*/

import java.io.*;
import java.util.*;

public class Queue {
   private Node front;
   private Node back;
   private int numWaiting;
      
   // deafult constructor creates an empty queue
   public Queue(){
      front=back=null;
      numWaiting = 0; 
    }
   
   // add the element n to the queue
   public void enqueue(int n) {
     Node newNode = new Node(n,null);
     numWaiting++;
     if (numWaiting == 0)
        { front = back = newNode;}
     else
        { back.next = newNode;
          back = newNode;
        }
   } 
    // remove an element from the queue
   public void dequeue() {
      if (!isEmpty())
       { front = front.next;}
   }  
   // print the queue from  front to back
   public void print(){
      Node ptr = front;
      while (ptr != null)
        { System.out.println(ptr.value + " ");
          ptr = ptr.next;
        }
   
   }
   // returns true if the queue is empty
   public boolean isEmpty(){
      if (numWaiting == 0) return true;
      else return false;
   }   
          
   // count the number of nodes in the queue
   public int size(){
     return numWaiting;
   }
   // count all the odd value nodes in the queue
   public int oddCount(){
      int count = 0;
      Node ptr = front;
      while (ptr != null)
       { if (ptr.value%2 == 1)
             count++;
          ptr = ptr.next;
       }
   }
    
   private class Node{
      public int value;
      public Node next;
      public Node(int n, Node link){
          value = n; next = link;
      }
   }


}