//BARANDA, REGINE V.

//PANGILINAN, ANTHONET S.

//CCP1103 - ITCC

//HAPPY NUMBERS

​

using System;                    

public class happyNumbers

{  

    public static void Main(string[] args)

    {

                string input;

                int sum;

                int ones;

                int tens;

                int hundreds;

                int thousands;

                int tenThousands;

                int number;

​

                Console.Clear();

                Console.WriteLine("Happy Numbers");

​

​

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

                input = Console.ReadLine();

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

                {

                    if (number <= 0)

                    {

                        Console.WriteLine("Zero or negative input is not allowed.");

                    }

                    else if (number > 20000)

                    {

                        Console.WriteLine("Invalid input. Please input 1-20,000 only.");

                    }

                    else

                    {

                        for (int i = 0; i <= 50; i++)

                        {

                            if (number < 10 && number != 1)

                            {

                                 number = number * number;

                            }

                            else if (number >= 10 && number < 100)

                            {

                               ones = number % 10;

                               tens = number / 10;

                               sum = (ones * ones) + (tens * tens);

                               number = sum;

                            }

                            else if (number >= 100 && number <= 999)

                            { 

                                hundreds = number / 100;

                                tens = (number / 10) - (hundreds * 10);

                                ones = number - (hundreds * 100) - (tens * 10);

                                sum = (ones * ones) + (tens * tens) + (hundreds * hundreds);

                                number = sum;

                            }

                            else if (number >= 1000 && number < 10000)

                            {

                                ones = number % 10;

                                number = number / 10;

                                tens = number % 10;

                                number = number / 10;

                                hundreds = number % 10;

                                number = number / 10;

                                thousands = number % 10;

                                sum = (ones * ones) + (tens * tens) + (hundreds * hundreds) + (thousands * thousands);

                                number = sum;

                            }

                            else if (number >= 1-000 && number < 100000)

                            {

                                ones = number % 10;

                                number = number / 10;

                                tens = number % 10;

                                number = number / 10;

                                hundreds = number % 10;

                                number = number / 10;

                                thousands = number % 10;

                                number = number / 10;

                                tenThousands = number % 10;

                                sum = (ones * ones) + (tens * tens) + (hundreds * hundreds) + (thousands * thousands) + (tenThousands * tenThousands);

                                number = sum;

                            }

                        }

                        if (number == 1)

                        {

                            Console.WriteLine(input + " is a happy number.");

                        }

                        else

                        {

                            Console.WriteLine(input + " is not a happy number.");

                        }

                    }

                }

                else

                {

                    Console.WriteLine("Invalid Input. Please Enter a numeric value.");

                }

        }

}

​

​