Reverse a Number

Reverse the digits of a number using a loop.

JavaBeginner
Java
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a number: ");
        int n = sc.nextInt();

        int rev = 0;
        while (n != 0) {
            int d = n % 10;
            rev = rev * 10 + d;
            n /= 10;
        }

        System.out.println("Reversed number = " + rev);
        sc.close();
    }
}

Output

Enter a number: 1234
Reversed number = 4321

We repeatedly take the last digit and build a new reversed number.