ArrayDeque in Java

// Java Program to demonstrates 
// the working of ArrayDeque
import java.util.ArrayDeque;
import java.util.Deque;

public class Geeks {
    
    public static void main(String[] args) {
        
        Deque<Integer> d = new ArrayDeque<>();
        d.addFirst(1);
        d.addLast(2);
        int f = d.removeFirst();
        int l = d.removeLast();
        System.out.println("First: " + f + ", Last: " + l);
    }
}

// Java Program to demonstrates 
// the working of ArrayDeque()
import java.util.ArrayDeque;

public class Geeks {
    public static void main(String[] args) {
        
        // Empty d with default capacity
        ArrayDeque<Integer> d = new ArrayDeque<>(); 
        d.add(10);
        d.add(20);
        System.out.println("ArrayDeque: " + d);  
    }
}

// Java Program to demonstrates the working of
// ArrayDeque(Collection<? extends E> c)
import java.util.ArrayDeque;
import java.util.Arrays;

public class Geeks {
    public static void main(String[] args)
    {
        ArrayDeque<Integer> d
            = new ArrayDeque<>(Arrays.asList(1, 2, 3, 4));
        System.out.println("ArrayDeque: " + d);
    }
}

// Java Program to demonstrates the working of
// ArrayDeque(int numofElements)
import java.util.ArrayDeque;

public class Geeks {
    public static void main(String[] args)
    {
        ArrayDeque<Integer> d = new ArrayDeque<>(10);
        d.add(5);
        d.add(15);
        System.out.println("ArrayDeque: " + d);
    }
}

// Java program to demonstrates 
// Addition of elements in ArrayDeque
import java.io.*;
import java.util.*;
public class Geeks {

    public static void main(String[] args)
    {
        // Initializing a deque
        // since deque is an interface
        // it is assigned the
        // ArrayDeque class
        Deque<String> d = new ArrayDeque<String>();

        // add() method to insert
        d.add("The");
        d.addFirst("To");
        d.addLast("Geeks");

        // offer() method to insert
        d.offer("For");
        d.offerFirst("Welcome");
        d.offerLast("Geeks");

        System.out.println("ArrayDeque : " + d);
    }
}

// Java program to Access Elements of ArrayDeque
import java.io.*;
import java.util.*;
public class Geeks {

    public static void main(String args[])
    {
        // Creating an empty ArrayDeque
        ArrayDeque<String> d
                = new ArrayDeque<String>();

        // Using add() method to add elements into the Deque
        // Custom input elements
        d.add("Welcome");
        d.add("To");
        d.add("Geeks");
        d.add("for");
        d.add("Geeks");

        // Displaying the ArrayDeque
        System.out.println("ArrayDeque: " + d);

        // Displaying the First element
        System.out.println("The first element is: "
                + d.getFirst());

        // Displaying the Last element
        System.out.println("The last element is: "
                + d.getLast());
    }
}

// Java program to demomstrates 
// Removal Elements in Deque
import java.util.*;
public class Geeks {
    public static void main(String[] args) {
        
        // Initializing a deque
        Deque<String> d = new ArrayDeque<String>();

        // Adding elements
        d.add("Java");
        d.addFirst("C++");
        d.addLast("Python");

        // Printing initial elements
        System.out.println("Initial Deque: " + d);

        // Removing elements as a stack from top/front
        System.out.println("Removed element using pop(): " + d.pop());

        // Removing an element from the front
        System.out.println("Removed element using poll(): " + d.poll());

        // Removing an element from the front using pollFirst
        System.out.println("Removed element using pollFirst(): " + d.pollFirst());

        // The deque is empty now
        System.out.println("Final Deque: " + d);
    }
}

// Java program to Illustrate 
// Iteration of Elements in Deque
import java.util.*;
public class Geeks {
    public static void main(String[] args)
    {
        // Declaring and initializing an deque
        Deque<String> d = new ArrayDeque<String>();

        // Adding elements at the back
        // using add() method
        d.add("For");

        // Adding element at the front
        // using addFirst() method
        d.addFirst("Geeks");

        // add element at the last
        // using addLast() method
        d.addLast("Geeks");
        d.add("is so good");

        // Iterate using Iterator interface
        // from the front of the queue
        System.out.println("Iterating in ForwardOrder:");
        for (Iterator i = d.iterator(); i.hasNext();) {

            // Print the elements
            System.out.print(i.next() + " ");
        }

        // New line
        System.out.println();

        // Iterate in reverse sequence in a queue
        System.out.println("Iterating in ReverseOrder:");
        for (Iterator i = d.descendingIterator();
             i.hasNext();) {

            System.out.print(i.next() + " ");
        }
    }
}