05. Special Numbers

using System;

namespace _05._Special_Numbers
{
    class SpecialNumbers
    {
        static void Main(string[] args)
        {
            //A number is special when its sum of digits is 5, 7 or 11.
            //Write a program to read an integer n and for all numbers in the range 1…n to print the number and if it is special or not
            //(True / False).

            int n = int.Parse(Console.ReadLine());
            //356
            //356 % 10 -> 6 !
            //356 / 10 -> 35
            //35 % 10 -> 5 !
            //35 / 10 -> 3
            //3 % 10 -> 3!
            // 3 / 10 -> 0

            for (int i = 1; i <= n; i++)
            {
                int sum = 0;
                int current = i;

                while (current > 0)
                {
                    sum += current % 10;
                    current = current / 10;
                }
                bool isSpecial = false;
                isSpecial = (sum == 5 || sum == 7 || sum == 11);
                Console.WriteLine($"{i} -> {isSpecial}");
            }
        }
    }
}