using System;

public class Program

{

    public static void Main()

    {

        do

        {

            Console.Write("\n\nPlease choose a method to test.\n\nThe avaible methods are:\nNotFizzBuzz\nNotFizzBuzzPQ\nFibonacci\nXML\n\nType your entry here: ");

            string methodChoice = Console.ReadLine().Trim();

            if (methodChoice.Equals("NotFizzBuzz", StringComparison.OrdinalIgnoreCase))

            {

                Console.WriteLine("NotFizzBuzz");

                //NotFizzBuzz

            }

            else if (methodChoice.Equals("NotFizzBuzzPQ", StringComparison.OrdinalIgnoreCase))

            {

                Console.WriteLine("NotFizzBuzzPQ");

                //NotFizzBuzzPQ

            }

            else if (methodChoice.Equals("Fibonacci", StringComparison.OrdinalIgnoreCase))

            {

                Console.WriteLine("Fibonacci");

                //Fibonacci

            }

            else if (methodChoice.Equals("XML", StringComparison.OrdinalIgnoreCase))

            {

                Console.WriteLine("XML");

                //XML

            }

            else

            {

                Console.WriteLine("Please enter a valid choice!");

            }

        } while(true);

    }

    interface ICodeTest

    {

        void NotFizzBuzz(int n);

        void NotFizzBuzzPQ(int n, int p, int q);

        void Fibonacci(int start, int length);

        void XML();

    }

​

    class Service : ICodeTest

    {

        public void NotFizzBuzz(int n)

        {

            int x = 0;

            for (int i = 1; i <= n; i++)

            {

                x = i;

                if (x % 5 != 0 && x % 7 != 0)

                {

                    Console.WriteLine(x);

                }

                else if (x % 5 == 0 && x % 7 == 0)

                {

                    Console.WriteLine(x + " " + "HelloWorld");

                }

                else if (x % 5 == 0)

                {

                    Console.WriteLine(x + " " + "Hello");

                }

                else if (x % 7 == 0)

                {

                    Console.WriteLine(x + " " + "World");

                }

            }

        }

        public void NotFizzBuzzPQ(int n, int p, int q)

        {

            int x = 0;

            for (int i = 1; i <= n; i++)

            {

                x = i;

                if (x % p != 0 && x % q != 0)

                {

                    Console.WriteLine(x);

                }

                else if (x % p == 0 && x % q == 0)

                {

                    Console.WriteLine(x + " " + "HelloWorld");

                }

                else if (x % p == 0)

                {

                    Console.WriteLine(x + " " + "Hello");

                }

                else if (x % q == 0)

                {

                    Console.WriteLine(x + " " + "World");

                }

            }

        }

        int PreviousFib(int n)

        {

            double a = n / ((1 + Math.Sqrt(5)) / 2.0);

            return (int)Math.Round(a);

        }

        public void Fibonacci(int start, int length)

        {

            int next = start;

            int first = PreviousFib(start);

            int last = 0;

            Console.Write(next + " ");

            for (int i = 1; i <= length; i++)

            {

                last = first + next;

                Console.Write(last + " ");

                first = next;

                next = last;

            }

        }

        public void XML()

        {

            throw new NotImplementedException("Method not implemented");

        }

    }

}

​