peekFirst : Retrieves the first element of this deque

E peekFirst()

Retrieves, but does not remove, the first element of this deque.

import java.util.*;

class DequePeekFirst{
 public static void main(String args[]){
  Deque<Integer> myDeque = new LinkedList<Integer> ();
  
  /* Add Elements to the myDeque */
  myDeque.add(10);
  myDeque.add(20);
  myDeque.add(30);
  myDeque.add(40);
  
  System.out.println("Elements in the myDeque are " +myDeque);
  
  System.out.println("\nRetrieving the First Element Of the Deque " + myDeque.peekFirst());
  System.out.println("Elements in the myDeque are " +myDeque);
  
  System.out.println("\nRetrieving the First Element Of the Deque " + myDeque.peekFirst());
  System.out.println("Elements in the myDeque are " +myDeque); 
 }
}

Output

Elements in the myDeque are [10, 20, 30, 40]

Retrieving the First Element Of the Deque 10
Elements in the myDeque are [10, 20, 30, 40]

Retrieving the First Element Of the Deque 10
Elements in the myDeque are [10, 20, 30, 40]

1. returns null if this deque is empty.

import java.util.*;

class DequePeekFirstNull{
 public static void main(String args[]){
  Deque<Integer> myDeque = new LinkedList<Integer> ();
  
  System.out.println("Elements in the myDeque are " +myDeque); 
  System.out.println("\nRetrieving the First Element Of the Deque " + myDeque.peekFirst());
 }
}

Output

Elements in the myDeque are []

Retrieving the First Element Of the Deque null

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