SumUpToN.java

import java.util.Scanner;

public class SumUpToN {

    // Recursive method to calculate the sum of integers up to n
    public static int sumUpToN(int n) {
        // Base case: if n is 0, return 0
        if (n == 0) {
            return 0;
        }
        // Recursive case: add n to the sum of integers up to n-1
        return n + sumUpToN(n - 1);
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        System.out.print("Enter a positive integer up to which you want to add: ");
        try {
            int userInput = scanner.nextInt();
            if (userInput < 0) {
                System.out.println("Please enter a positive integer.");
            } else {
                if (userInput > 100) {
                    System.out.println("Please enter an integer up to 100.");
                    return;
                } else {
                    int result = sumUpToN(userInput);
                    System.out.println("The sum of integers up to " + userInput + " is: " + result);
                }
            }
        } catch (Exception e) {
            System.out.println("Sorry, this is not a good input, try again.");
        } finally {
            scanner.close();
        }
    }
}