public class SumFinder {

    public static void main(String[] args) {
        int n = findNumberWithIdenticalDigits();
        int sum = calculateSum(n);
        System.out.println("The number is " + n + " and the sum from 1 to " + n + " is " + sum);
    }

    private static int findNumberWithIdenticalDigits() {
        int n = 1;
        while (true) {
            int sum = calculateSum(n);
            if (hasIdenticalDigits(sum)) {
                return n;
            }
            n++;
        }
    }

    private static int calculateSum(int n) {
        return (n * (n + 1)) / 2;
    }

    private static boolean hasIdenticalDigits(int number) {
        String numberStr = String.valueOf(number);
        char digit = numberStr.charAt(0);
        for (int i = 1; i < numberStr.length(); i++) {
            if (numberStr.charAt(i) != digit) {
                return false;
            }
        }
        return true;
    }
}

var = sum*sum

var = pow(sum, 2)

#include <math.h>

#include <iostream>

using namespace std;

enum Option { A, B, C, D };

int main()
{
    Option userChoice;

    cout << "Please answer this question to skip:" << endl;
    cout << "The result of 4+5 is:" << endl;
    cout << "A) 6\nB) 7\nC) 9\nD) 0\n" << endl;

    char userAnswer;

    cin >> userAnswer;

    switch (userAnswer)
    {
        case 'C':
        case 'c':
            userChoice = C;
            cout << "Right! This is great, expand!" << endl;
            break;
        default:
            cout << "This is an error! The correct answer is C." << endl;
            break;
    }

    return 0;
}