1. Introduction

Natural numbers are the set of positive integers starting from 1 and increasing without bound. The sum of natural numbers can be calculated using a formula, but in this blog, we’ll see how to calculate it using a simple Java program. We will calculate the sum of the first n natural numbers, where n is a user-input value.

2. Program Steps

1. Declare a class named SumOfNaturalNumbers.

2. Inside this class, define the main method.

3. In the main method, create a Scanner object to read user input.

4. Prompt the user to enter a natural number n.

5. Declare a variable sum and initialize it to 0.

6. Create a loop to iterate from 1 to n.

7. In each iteration, add the loop variable to the sum.

8. After the loop ends, print the calculated sum.

3. Code Program

import java.util.Scanner; // Import Scanner class

public class SumOfNaturalNumbers { // Step 1: Declare a class named SumOfNaturalNumbers

    public static void main(String[] args) { // Step 2: Define the main method

        Scanner sc = new Scanner(System.in); // Step 3: Create Scanner object to read input

        System.out.println("Enter a natural number n: "); // Step 4: Prompt the user to enter a natural number n
        int n = sc.nextInt(); // Read the user input

        int sum = 0; // Step 5: Declare and initialize sum to 0

        // Step 6: Create a loop to iterate from 1 to n
        for (int i = 1; i <= n; i++) {

            sum += i; // Step 7: In each iteration, add the loop variable to the sum
        }

        // Step 8: Print the calculated sum
        System.out.println("The sum of the first " + n + " natural numbers is: " + sum);
    }
}

Output:

Enter a natural number n:
10
The sum of the first 10 natural numbers is: 55

4. Step By Step Explanation

– Step 1: A class named SumOfNaturalNumbers is declared.

– Step 2: The main method is defined inside the SumOfNaturalNumbers class.

– Step 3: A Scanner object is created to read the user input.

– Step 4: The user is prompted to enter a natural number n.

– Step 5: A variable sum is declared and initialized to 0.

– Step 6: A for loop is created to iterate from 1 to n.

– Step 7: In each iteration of the loop, the loop variable i is added to the sum.

– Step 8: After the loop ends, the calculated sum of the first n natural numbers is printed to the console.