Computing the Sum of Digits of a Number Using While Loop in Java

Calculating the sum of digits of a number is a common programming task. In this tutorial, we will explore how to find the sum of digits of a number using a while loop in Java. This step-by-step guide is tailored for new learners and aims to explain the concept, syntax, and provide examples of using a while loop to compute the sum of digits.

Understanding the Sum of Digits

The sum of digits refers to the result obtained by adding up all the individual digits of a given number. For instance, the sum of digits of the number 123 is 1 + 2 + 3 = 6.

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Syntax of the While Loop

The syntax for a while loop in Java is as follows:

while (condition) {
// Code block to be executed repeatedly while the condition is true
// Typically, there should be a way to modify the condition inside the loop
}

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Implementing the Program: Step-by-Step

Let’s break down the implementation of the program into step-by-step instructions:

  • Step 1: Take an integer input for which you want to compute the sum of digits.
  • Step 2: Initialize a variable num with the input number.
  • Step 3: Initialize a variable sum to store the sum of digits and set it to 0.
  • Step 4: Use a while loop with the condition num > 0 to iterate until num becomes 0.
  • Step 5: Extract the last digit of num using the modulus operator % and add it to sum.
  • Step 6: Update num by dividing it by 10, discarding the last digit.
  • Step 7: Repeat steps 5 and 6 until num becomes 0.
  • Step 8: After the loop ends, print the final value of sum, which represents the sum of digits of the input number.
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Example: Computing the Sum of Digits

Let’s consider an example where we want to find the sum of digits of the number 123:

int num = 123;
int sum = 0;

while (num > 0) {
int digit = num % 10;
sum += digit;
num /= 10;
}

System.out.println(“Sum of digits: ” + sum);

The output for this example will be: “Sum of digits: 6”.

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Conclusion

By utilizing a while loop in Java, we can effectively compute the sum of digits of a given number. The program we discussed simplifies this task by extracting digits one by one and accumulating their sum. Understanding the syntax and examples provided will enable you to apply similar logic in your Java programs effectively.

Keep practicing and exploring the possibilities of while loops in Java coding. Happy programming!

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