Java Lambda Expression: Find second largest and smallest element in an Array

Java Lambda Program: Exercise-19 with Solution

Write a Java program to implement a lambda expression to find the second largest and smallest element in an array.

Sample Solution:

Java Code:

import java.util.Arrays;
import java.util.Comparator;

public class Main {
  public static void main(String[] args) {
    // Create an array of integers
    Integer[] nums = {
      1,
      7,
      18,
      25,
      77,
      300,
      101
    };
    System.out.println("Array elements: " + Arrays.toString(nums));
    // Find the second largest element using lambda expression
    Integer secondLargest = Arrays.stream(nums)
      .distinct()
      .sorted(Comparator.reverseOrder())
      .skip(1)
      .findFirst()
      .orElse(null);

    // Find the second smallest element using lambda expression
    Integer secondSmallest = Arrays.stream(nums)
      .distinct()
      .sorted()
      .skip(1)
      .findFirst()
      .orElse(null);

    // Print the results
    System.out.println("Second largest element: " + secondLargest);
    System.out.println("Second smallest element: " + secondSmallest);
  }
}

Sample Output:

Array elements: [1, 7, 18, 25, 77, 300, 101]
Second largest element: 101
Second smallest element: 7

Explanation:

In the above exercise,

• Import the necessary classes Arrays and Comparator.
• In the main method, we create an array of integers named numbers.

To find the second largest element:

• Use the Arrays.stream method to convert the array into a stream of integers.
• Apply the distinct operation to remove any duplicate elements.
• Sort the elements in reverse order using Comparator.reverseOrder().
• Skip the first element (the largest) using skip(1).
• Find the first element remaining, which will be the second largest, using findFirst().
• If the stream is empty, we return null using orElse(null).
• The result is stored in the variable secondLargest.

To find the second smallest element:

• Follow a similar process as above, but this time we sort the elements in ascending order using the default comparator.
• The result is stored in the variable secondSmallest.

Finally, we print the second largest and second smallest elements to the console.

Flowchart:

Live Demo:

Java Code Editor:

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