Reverse a Number

Reverse the digits of a number using a loop.

BeginnerTopic: Module 3: Loop Programs
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Java Reverse a Number Program

This program helps you to learn the fundamental structure and syntax of Java programming.

Try This Code
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

Understanding Reverse a Number

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

Note: To write and run Java programs, you need to set up the local environment on your computer. Refer to the complete article Setting up Java Development Environment. If you do not want to set up the local environment on your computer, you can also use online IDE to write and run your Java programs.

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Sum of Digits
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Factorial
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Sum of Digits

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