Reverse a Number in Java: Explanation & Practice

Problem summary

Write a program that reverses the digits of a given number. Your code should work for ANY positive integer.

Starter code

public class Main {
    public static void main(String[] args) {
        int number = 12345; // Test case 1
        
        // Write code to reverse the number
        // Should work for ANY number
        // Print: Reversed: <result>
    }
}

Expected output and test cases

• 12345 → 54321

  Reversed: 54321

• 1234 → 4321

  Reversed: 4321

• 1 → 1

  Reversed: 1

Hints

1. Build the reversed number digit by digit
2. Use modulus to get last digit, divide to remove it
3. Multiply result by 10 before adding each digit

Related Core Java Basics exercises

• Practice Modulus Operator in Java
• Practice Sum of Digits in Java
• Practice Count Digits in Java

Practice all Core Java Basics exercises · Run this idea in the Java compiler