Java Program to Get First and Last Elements from an Array List

JavaCampus InterviewServer Side ProgrammingProgramming

In this article, we will understand how to get first and last elements from an array list. A list is an ordered collection that allows us to store and access elements sequentially. It contains the index-based methods to insert, update, delete and search the elements. It can also have the duplicate elements.

Below is a demonstration of the same −

Suppose our input is

Input list: [40, 60, 150, 300]

The desired output would be

The first element is : 40
The last element is : 300

Algorithm

Step 1 - START
Step 2 - Declare ArrayList namely input_list.
Step 3 - Define the values.
Step 4 - Check of the list is not an empty list. Use the .get(0) and .get(list.size - 1) to get the first
and last elements.
Step 5 - Display the result
Step 6 - Stop

Example 1

Here, we bind all the operations together under the ‘main’ function.

import java.util.ArrayList;
public class Demo {
   public static void main(String[] args){
      ArrayList<Integer> input_list = new ArrayList<Integer>(5);
      input_list.add(40);
      input_list.add(60);
      input_list.add(150);
      input_list.add(300);
      System.out.print("The list is defined as: " + input_list);
      int first_element = input_list.get(0);
      int last_element = input_list.get(input_list.size() - 1);
      System.out.println("\nThe first element is : " + first_element);
      System.out.println("The last element is : " + last_element);
   }
}

Output

The list is defined as: [40, 60, 150, 300]
The first element is : 40
The last element is : 300

Example 2

Here, we encapsulate the operations into functions exhibiting object oriented programming.

import java.util.ArrayList;
public class Demo {
   static void first_last(ArrayList<Integer> input_list){
      int first_element = input_list.get(0);
      int last_element = input_list.get(input_list.size() - 1);
      System.out.println("\nThe first element is : " + first_element);
      System.out.println("The last element is : " + last_element);
   }
   public static void main(String[] args){
      ArrayList<Integer> input_list = new ArrayList<Integer>(5);
      input_list.add(40);
      input_list.add(60);
      input_list.add(150);
      input_list.add(300);
      System.out.print("The list is defined as: " + input_list);
      first_last(input_list);
   }
}

Output

The list is defined as: [40, 60, 150, 300]
The first element is : 40
The last element is : 300
raja
Updated on 29-Mar-2022 12:36:30

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