Write a java method to reverse the elements of an array using recursion. Your method should take an array as an input parameter and return reverse the array

Break Down the Problem

1. Identify the base case for recursion.
2. Determine how to break down the array into smaller parts.
3. Implement the recursive function to reverse the array.

Relevant Concepts

• Recursion is a method where the solution to a problem depends on solutions to smaller instances of the same problem.
• We will use an array and swap elements to reverse it.

Analysis and Detail

1. Base case: If the array length is 0 or 1, return the array as it is already reversed.
2. Recursive case: Swap the first and last elements and call the method recursively on the subarray that excludes these two elements.

Implementation

Here is the Java method to reverse an array using recursion:

public class ArrayReversal {
    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5};
        int[] reversedArr = reverseArray(arr);
        
        // Printing the reversed array
        for (int num : reversedArr) {
            System.out.print(num + " ");
        }
    }
    
    public static int[] reverseArray(int[] arr) {
        // Call the helper method with the full length of the array
        reverse(arr, 0, arr.length - 1);
        return arr;
    }
    
    public static void reverse(int[] arr, int start, int end) {
        // Base case: if start is greater than or equal to end
        if (start >= end) {
            return;
        }
        
        // Swap the elements at start and end
        int temp = arr[start];
        arr[start] = arr[end];
        arr[end] = temp;
        
        // Recursive call for the next pair
        reverse(arr, start + 1, end - 1);
    }
}

Final Answer

The method reverseArray takes an integer array as input and reverses its elements using recursion. The output for the array {1, 2, 3, 4, 5} will be {5, 4, 3, 2, 1} after execution.