public class IntQueue {

    private int[] items_;
    private int top_;
    private int capacity_;
    private int iter_;

    public IntQueue(int capacity)
    {
        if(capacity <=0) capacity = 10;

        capacity_ = capacity;
        top_=0;
        count_ = 0;
        iter_=0;

        items_= new int[capacity_];
    }

    public void push_back(int value)
    {
        if(top_>= capacity_)
            overflow();

        items_[top_++]=value;
        count_++;
    }

    public int front()
    {
        if(top_<=0)
            return 0;

        int temp=0;
        temp=items_[iter_];

        count_--;
        iter_++;
        return temp;

    }

    public IntQueue clone()
    {
        IntQueue result = new IntQueue(capacity_);

        for(int i=0 ; i<top_; ++i)
        {
            result.push_back(items_[i]);

        }

        /*for(int i=0 ; i<top_ ; ++i)
        {

            result.items_[i] = items_[i];
        }*/

        return result;

    }

    public void log()
    {

        for(int i=0 ; i <top_; ++i)
        {
            System.out.print(items_[i]);
            if(i<top_ -1)
                System.out.print(", ");
        }
        System.out.println();
        }

    }

    private void overflow()
    {
        int[] newItem = new int[capacity_*2];

        for(int i=0 ; i <top_; ++i)
            newItem[i] = items_[i];
        items_=newItem;
        capacity_ *=2;

    }

    public static void main(String args[])
    {
        IntQueue queue = new IntQueue(2);

        System.out.println("queue push 3: "); queue.push_back(3);
        System.out.println("queue push 2: "); queue.push_back(2);
        System.out.println("queue push 1: "); queue.push_back(1);

        System.out.print("queue log: "); queue.log();

        System.out.println("front " + queue.front());
        System.out.println("front " + queue.front());

        System.out.print("queue log: "); queue.log();

        System.out.println("queue push 12: "); queue.push_back(12);
        System.out.println("queue push 11: "); queue.push_back(11);
        System.out.println("queue push 21: "); queue.push_back(21);
        System.out.println("queue push 31: "); queue.push_back(31);

        System.out.print("queue log: "); queue.log();

        System.out.println("front " + queue.front());
        System.out.println("front " + queue.front());

        System.out.print("clone queue log: "); queue.clone().log();


    }

}

void removeAt(int i) {
        final E[] items = this.items;
        // if removing front item, just advance
        if (i == takeIndex) {
            items[takeIndex] = null;
            takeIndex = inc(takeIndex);
        } else {
            // slide over all others up through putIndex.
            for (;;) {
                int nexti = inc(i);
                if (nexti != putIndex) {
                    items[i] = items[nexti];
                    i = nexti;
                } else {
                    items[i] = null;
                    putIndex = i;
                    break;
                }
            }
        }
        --count;
        notFull.signal();
    }

import java.util.Iterator;
import java.util.LinkedList;
import java.util.Queue;

public class QueueExample {

    public static void main(String[] args) {

        Queue<String> qe=new LinkedList<String>();

        qe.add("b");
        qe.add("a");
        qe.add("c");
        qe.add("e");
        qe.add("d");

        Iterator it=qe.iterator();

        System.out.println("Initial Size of Queue :"+qe.size());

        while(it.hasNext())
        {
            String iteratorValue=(String)it.next();
            System.out.println("Queue Next Value :"+iteratorValue);
        }

        // get value and does not remove element from queue
        System.out.println("Queue peek :"+qe.peek());

        // get first value and remove that object from queue
        System.out.println("Queue poll :"+qe.poll());

        System.out.println("Final Size of Queue :"+qe.size());
    }
}

int queue[SIZE];
int first = 0;
int last = 0;

void enque(int i) {
    if(last == SIZE)
        throw new RuntimeExeption("Queue is full");
    queue[last++] = i;
}

int deque() {
    if(first == last)
        throw new RuntimeExeption("Queue is empty");
    return queue[first++];
}

import java.io.*;
 import java.lang.*;
 class clrqueue
 {
  DataInputStream get=new DataInputStream(System.in);
  int a[];
  int i,front=0,rear=0,n,item,count=0;
  void getdata()
  {
  try
   {
   System.out.println("Enter the limit");
   n=Integer.parseInt(get.readLine());
   a=new int[n];
   }
  catch(Exception e)
   {
   System.out.println(e.getMessage());
   }
  }
  void enqueue()
  {
   try
   {
   if(count<n)
    {
    System.out.println("Enter the element to be added:");
    item=Integer.parseInt(get.readLine());
    a[rear]=item;
     rear++;
    count++;
    }
   else
    System.out.println("QUEUE IS FULL");
   }
  catch(Exception e)
   {
   System.out.println(e.getMessage());
   }
  }
  void dequeue()
  {
   if(count!=0)
    {
    System.out.println("The item deleted is:"+a[front]);
    front++;
    count--;
    }
   else
    System.out.println("QUEUE IS EMPTY");
  if(rear==n)
   rear=0;
  }
  void display()
  {
   int m=0;
   if(count==0)
   System.out.println("QUEUE IS EMPTY");
   else
   {
   for(i=front;m<count;i++,m++)
   System.out.println(" "+a[i]);
   }
  }
 }
 class Myqueue
 {
  public static void main(String arg[])
  {
  DataInputStream get=new DataInputStream(System.in);
  int ch;
  clrqueue obj=new clrqueue();
  obj.getdata();
  try
  {
   do
   {
   System.out.println(" 1.Enqueue  2.Dequeue  3.Display  4.Exit");
   System.out.println("Enter the choice");
   ch=Integer.parseInt(get.readLine());
   switch (ch)
   {
   case 1:
       obj.enqueue();
      break;
   case 2:
      obj.dequeue();
      break;
   case 3:
      obj.display();
      break;
   }
   }
   while(ch!=4);
  }
  catch(Exception e)
  {
  System.out.println(e.getMessage());
  }
  }
 }