Dart Program – Sum of Squares of First N Natural Numbers

Sum of Squares of First N Natural Numbers

To find the sum of squares of first N natural numbers in Dart, we may use the direct mathematical formula or  use a For loop to iterate from 1 to N and accumulate the sum of squares. In this tutorial, we will write programs using each of the said approaches.

Dart Program

Find the sum of squares using For Loop

In the following program, we read a number into n, and find the sum of squares first n natural numbers using a For Loop.

main.dart

import 'dart:io';

void main(){
    //read n from user
    print('Enter n');
    var n = int.parse(stdin.readLineSync()!);

    //initialize sum to 0
    var sum = 0;

    //accumulate the sum of squares
    for(var i = 1; i <= n; i++) {
        sum += i * i;
    }

    print('sum = $sum');
}

Output

Enter n
10
sum = 385

Output

Enter n
3
sum = 14

Find the sum of squares using mathematical formula

In the following program, we read a number into n, and find the sum of squares of the first n natural numbers using the below formula.

sum = n * (n + 1) * (2*n + 1) / 6

main.dart

import 'dart:io';

void main(){
    //read n from user
    print('Enter n');
    var n = int.parse(stdin.readLineSync()!);

    var sum = n * (n + 1) * (2 * n + 1) / 6;
    print('sum = $sum');
}

Output

Enter n
10
sum = 55.0

Output

Enter n
100
sum = 338350.0

Summary

In this Dart Tutorial, we learned how to find the sum of squares of the first n natural numbers.