Sum of Digits in Java: Explanation & Practice

Problem summary

Write a program that calculates the sum of all digits in 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 calculate sum of digits
        // Should work for ANY number, not just 12345
        // Print: Sum of digits: <result>
    }
}

Expected output and test cases

• 12345 → 1+2+3+4+5 = 15

  Sum of digits: 15

• 1234 → 1+2+3+4 = 10

  Sum of digits: 10

• 123 → 1+2+3 = 6

  Sum of digits: 6

Hints

1. Use a while loop to extract each digit
2. number % 10 gives the last digit
3. number / 10 removes the last digit

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• Practice Modulus Operator in Java
• Practice Reverse a Number in Java

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