Example: Sum of Natural Numbers (Iterative) in Java

C
C++
C#
Java
Python
PHP
// Sum of Natural Numbers (Iterative)
import java.util.Scanner;

// Main class containing the entry point of the program
public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        // Step 1: Prompt user for input
        System.out.print("Enter a positive integer (n): ");
        int n = scanner.nextInt();

        // Step 2: Validate input
        if (n < 0) {
            System.out.println("Please enter a non-negative integer.");
        } else {
            // Step 3: Calculate sum iteratively
            int sum = 0;
            for (int i = 1; i <= n; i++) {
                sum += i;
            }

            // Step 4: Display the result
            System.out.println("The sum of natural numbers up to " + n + " is: " + sum);
        }

        scanner.close();
    }
}