How to insert element at start of ArrayDeque in Java ?
Declaration :
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public void addFirst(E e) |
Explanation :
| Purpose | The java.util.ArrayDeque.addFirst(E e) method inserts the specified element E at the front of the deque. |
| Parameters | e ===> The element to be added in the deque. |
| Return Value | This method does not return any value. |
| Exception | NullPointerException — if the specified element is null. |
Java Program : Example
Below example will explain java.util.ArrayDeque.addFirst(E) method.
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package com.c4learn; import java.util.ArrayDeque; import java.util.Deque; public class ArrayDequeDemo { public static void main(String[] args) { // Create empty array deque with an initial capacity Deque<Integer> deque = new ArrayDeque<Integer>(8); // Use add() method to add elements deque.add(100); deque.add(200); deque.add(300); deque.add(400); deque.add(500); // Use addFirst() method to add elements deque.addFirst(111); deque.addFirst(222); deque.addFirst(333); // Print all the elements available in deque for (Integer number : deque) { System.out.println("Element is " + number); } } } |
Output of Program :
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Element is 333 Element is 222 Element is 111 Element is 100 Element is 200 Element is 300 Element is 400 Element is 500 |