//POLICARPIO, JOHN DANIEL

//RAMIREZ, KATE PRINCESS B

//CCP 1103-ITBC

//HAPPY NUMBER

using System;

​

public class Program

{

    public static void Main()

    {

        string input = "";

        int number = 0;

        int values = 0;

        char[] array = new char[] { };

        Console.Write("Enter a number:");

        input = Console.ReadLine();

        array = input.ToCharArray();

​

        if (Int32.TryParse(input, out number))

        {

            if (number < 1)

            {

                Console.WriteLine("\nZero and negative values is not allowed.");

            }

            else

            {

                if (number < 20001)

                {

                    while (input.Length != 1)

                    {

                        for (int i = 0; i < array.GetLength(0); i++)

                        {

                            values += (int)Math.Pow(Int32.Parse(array[i].ToString()), 2);

                        }

                        input = values.ToString();

                        values = 0;

                        array = input.ToCharArray();

                    }

                    if (input == "1")

                    {

                        Console.WriteLine("\n{0} is happy number.", number);

                    }

                    else

                    {

                        Console.WriteLine("\n{0} is not happy number.", number);

                    }

                }

                else

                {

                    Console.WriteLine("\nThe number that input by the user exceeds the limit of the program\nThe program can only holds from 1 to 20,000");

                }

            }

        }

        else

        {

            Console.WriteLine("\nThe number that input by the user consist of non numerical value.");

        }

    }

}