Calculate Sum of Digits of a Number In Dart Programming

In this Post, we’ll explore different ways to calculate the sum of digits in Dart Programming, with clear code examples and explanations.

Calculate Sum of Digits of a Number In Dart Programming

Getting Started

Working with numbers is a common task in programming, and one of the such task is calculating the sum of digits of a number. Dart, a modern object-oriented language developed by Google, makes this operation straightforward with its powerful standard library and easy-to-read syntax.

In programming, the sum of digits refers to the total obtained by adding each digit of a number. Here, we will see how to achieve this using the Dart programming language.

Example of Sum of Digits:

If a number is: 1234
Then sum of digits is: 1 + 2 + 3 + 4 = 10

Various Method of Calculating Sum of Digits

There are various ways to calculate the sum of digits of a number. Here, I am going to discuss two very common and easy methods of the Dart programming language, and I will also explain how each one works.

Method 1: Calculating Sum of Digits Using String Conversion

String Conversion method is the most simplest and readable method. This method involves converting the number to a string, iterating through each character, converting each back to an integer, and summing them.

Code Example

 import 'dart:io';  
 void main() {  
  // Asking for favourite number  
   print("Enter your favourite number:");  
  // Scanning number  
  int number =int.parse(stdin.readLineSync()!);  
  print('Sum of digits of $number is: ${number.toString()  
    .split('')  
    .map(int.parse)  
    .reduce((a, b) => a + b)}');  
 }

Input

Enter your favourite number: 6789

Output

Sum of digits of 6789 is: 30

How it Works:

number.toString() converts the integer to a string ("6789").
.split('') creates a list of characters (['6', '7', '8', '9']).
.map(int.parse) turns each character into an integer (['6', '7', '8', '9']).
.reduce((a, b) => a + b) sums the list.

Method 2: Calculating Sum of Digits Using a While Loop

This method uses arithmetic to extract digits, which avoids converting the number to a string.

Code Example

 import 'dart:io';  
 void main() {  
  // Asking for a favourite number  
   print("Enter your favourite number:");  
  // Scanning number  
  int number =int.parse(stdin.readLineSync()!);  
  //int number =7654;  
  int orgnumber=number;  
  int sum = 0;  
  while (number != 0) {  
   sum += number % 10;  
   number ~/= 10; // Integer division  
  }  
  print('Sum of digits of $orgnumber is: $sum');  
 }

Input

Enter your favourite number: 7654

Output

Sum of digits of 7654 is: 22

How it Works:

number % 10 gives the last digit.
Add it to sum.
number ~/= 10 removes the last digit.
Repeats until number is zero.

Summary

Calculating the sum of digits in Dart programming is a useful exercise in both string manipulation and basic arithmetic. Whether you're preparing for a coding interview or building an input validator, understanding this operation helps build stronger foundational skills in Dart.

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Calculate Sum of Digits of a Number In Dart Programming