using System;

​

namespace M4Activity1

{

    public class Program

    {

        public static void Main(string[] args)

        {

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

            int n = Convert.ToInt32(Console.ReadLine());

            SampleIf(n);

        }

​

        static void SampleIf(int x)

        {

            if (x == 0)

                Console.WriteLine("The number you entered is zero.");

            else if (x > 0)

            {

                Console.WriteLine("The number you entered is a positive integer.");

                SampleSwitch(x);

            }

            else

                Console.WriteLine("The number you entered is a negative integer.");

            return;

        }

​

        static void SampleSwitch(int x)

        {

            int ones = x % 10;

            int tens = x / 10;

            switch (tens)

            {

                case 1:

                    if (ones == 0)

                    {

                        Console.Write("Ten");

                    }

                    else if (ones == 1)

                    {

                        Console.Write("Eleven");

                    }

                    else if (ones == 2)

                    {

                        Console.Write("Twelve");

                    }

                    else if (ones == 3)

                    {

                        Console.Write("Thirteen");

                    }

                    else if (ones == 4)

                    {

                        Console.Write("Fourteen");

                    }

                    else if (ones == 5)

                    {

                        Console.Write("Fifteen");

                    }

                    else if (ones == 6)

                    {

                        Console.Write("Sixteen");

                    }

                    else if (ones == 7)

                    {

                        Console.Write("Seventeen");

                    }

                    else if (ones == ' ')

                    {

                        Console.Write("Eighteen");

                    }

                    else if (ones == 9)

                    {

                        Console.Write("Nineteen");

                    }

                    return;

                case 2:

                    Console.Write("Twenty ");

                    break;

                case 3:

                    Console.Write("Thirty ");

                    break;

                case 4:

                    Console.Write("Forty ");

                    break;

                case 5:

                    Console.Write("Fifty ");

                    break;

                case 6:

                    Console.Write("Sixty ");

                    break;

                case 7:

                    Console.Write("Seventy ");

                    break;

                case 8:

                    Console.Write("Eigthy ");

                    break;

                case 9:

                    Console.Write("Ninety ");

                    break;

            }

            switch (ones) { }

                if (tens != ones) {

                switch (ones) {

                    case 0:

                        Console.Write("");

                        break;

                    case 1:

                        Console.Write("one");

                        break;

                    case 2:

                        Console.Write("two");

                        break;

                    case 3:

                        Console.Write("three");

                        break;

                    case 4:

                        Console.Write("four");

                        break;

                    case 5:

                        Console.Write("five");

                        break;

                    case 6:

                        Console.Write("six");

                        break;

                    case 7:

                        Console.Write("seven");

                        break;

                    case 8:

                        Console.Write("eight");

                        break;

                    case 9:

                        Console.Write("nine");

                        break;

                }

            }

        }

    }

}