Daily Java Challenge #5 – Sum of Digits of a Number (Beginner Level)

Problem Statement

Write a Java program to find the sum of digits of a number entered by the user.

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Input

A number like:
1234

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Output

A message like:
Sum of digits = 10

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What Does “Sum of Digits” Mean?

You break the number into single digits and add them all together:

 1234 →
1 + 2 + 3 + 4 = 10

That’s the sum of digits!

Java Code

import java.util.Scanner;

public class SumOfDigits {
    public static void main(String[] args) {
        // Step 1: Ask the user for a number
        Scanner scanner = new Scanner(System.in);
        System.out.print(“Enter a number: “);
        int number = scanner.nextInt();

        int sum = 0;
        int temp = number;

        // Step 2: Break the number into digits and add them
        while (temp > 0) {
            int digit = temp % 10;  // Get last digit
            sum += digit;           // Add to sum
            temp = temp / 10;       // Remove last digit
        }

        // Step 3: Show the result
        System.out.println(“Sum of digits = ” + sum);
    }
}

Step-by-Step (Explained Like You’re New)

1. We take a number from the user.

2. We use % 10 to get the last digit.

3. We add that digit to a variable called sum.

4. Then we use / 10 to remove the last digit.

5. We repeat this until there are no digits left.

6. Finally, we show the total sum.

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Example

Input: 567
Calculation: 5 + 6 + 7 = 18
✅ Output: Sum of digits = 18

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Challenge for You

Try to write the same program using a String, by looping through each character and converting it to a number using Character.getNumericValue()!

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Come back tomorrow for Challenge #6!
One small Java program a day = Big progress over time.