Example: Reverse a Number Using Recursion in Java

// Reverse a Number Using Recursion
import java.util.Scanner;

// Main class containing the entry point of the program
public class Main {

    // Helper variable to store the reversed number
    static int reversedNumber = 0;

    // Recursive method to reverse a number
    public static void reverseNumber(int number) {
        // Base case: if the number becomes 0, stop recursion
        if (number == 0) {
            return;
        }

        // Step 1: Get the last digit of the number
        int lastDigit = number % 10;

        // Step 2: Append the last digit to the reversedNumber
        reversedNumber = reversedNumber * 10 + lastDigit;

        // Step 3: Recursively call the method with the remaining digits
        reverseNumber(number / 10);
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // Step 1: Prompt the user to enter a number
        System.out.print("Enter a number to reverse: ");
        int num = scanner.nextInt();

        // Step 2: Call the recursive method to reverse the number
        reverseNumber(num);

        // Step 3: Print the reversed number
        System.out.println("Reversed number: " + reversedNumber);

        scanner.close();
    }
}