ArrayDeque removeFirst() Method in Java
The Java.util.ArrayDeque.removeFirst() method is used to remove the first element of the Deque.
Syntax:
Array_Deque.removeFirst()
Parameters: The method does not take any parameters.
Return Value: This method returns the first element of the Deque after removing it.
Exceptions: The method throws NoSuchElementException is thrown if the deque is empty.
Below programs illustrate the Java.util.ArrayDeque.removeFirst() method:
Program 1:
// Java code to illustrate removeFirst() import java.util.*; public class ArrayDequeDemo { public static void main(String args[]) { // Creating an empty ArrayDeque Deque<String> de_que = new ArrayDeque<String>(); // Use add() method to add elements into the Deque de_que.add( "Welcome" ); de_que.add( "To" ); de_que.add( "Beginner" ); de_que.add( "For" ); de_que.add( "Beginner" ); // Displaying the ArrayDeque System.out.println( "Initial ArrayDeque: " + de_que); // Removing elements using removeFirst() method de_que.removeFirst(); de_que.removeFirst(); de_que.removeFirst(); // Displaying the ArrayDeque after removal System.out.println( "ArrayDeque after removing " + "elements: " + de_que); } } |
Output:
Initial ArrayDeque: [Welcome, To, Beginner, For, Beginner] ArrayDeque after removing elements: [For, Beginner]
Program 2:
// Java code to illustrate removeFirst() import java.util.*; public class ArrayDequeDemo { public static void main(String args[]) { // Creating an empty ArrayDeque Deque<Integer> de_que = new ArrayDeque<Integer>(); // Use add() method to add elements into the Deque de_que.add( 10 ); de_que.add( 15 ); de_que.add( 30 ); de_que.add( 20 ); de_que.add( 5 ); // Displaying the ArrayDeque System.out.println( "Initial ArrayDeque: " + de_que); // Removing elements using removeFirst() method de_que.removeFirst(); de_que.removeFirst(); // Displaying the ArrayDeque after removal System.out.println( "ArrayDeque after removing " + "elements: " + de_que); } } |
Output:
Initial ArrayDeque: [10, 15, 30, 20, 5] ArrayDeque after removing elements: [30, 20, 5]