using System;

​

interface IMath

{

    void run();

}

​

class twotwoseven : IMath

{

    public void run()

    {

        float x = (float)(22F / 7F);

        Console.WriteLine(x.ToString(".###########"));

    }

}

​

class threesevenseven : IMath

{

    public void run()

    {

        float x = (float)(377F / 120F);

        Console.WriteLine(x.ToString(".###########"));

    }

}

​

class sixtwoeightthreetwo : IMath

{

    public void run()

    {

        float x = (float)(62832F / 20000F);

        Console.WriteLine(x.ToString(".###########"));

    }

}

​

class Iowa : IMath

{

    public void run()

    {

        Console.WriteLine("3.2");

    }

}

​

class sqrootIowa : IMath

{

    public void run()

    {

        Console.WriteLine("1.429");

    }

}

​

class series : IMath

{

    public void run()

    {

        var k = 1D; // Initialize denominator

        var s = 0D; // Initialize sum

        for (long i = 0; i < 1000000; i += 1)

        {

            double x = (i % 2 == 0) ? s += (double)(4.0 / k) : s -= (double)(4.0 / k);

            k += 2.0D;

        }

​

        Console.WriteLine(s);

    }

}

​

class PiFactory

{

    public static IMath getPi(string piType)

    {

        switch (piType)

        {

            case "twotwoseven":

                return (new twotwoseven());

            case "threesevenseven":

                return (new threesevenseven());

            case "Iowa":

                return (new Iowa());

            case "sqrootIowa":

                return (new sqrootIowa());

            default:

                return (new series());

        }

    }

}

​

public class Program

{

    public static void Main()

    {

        IMath x = PiFactory.getPi("series");

        x.run();

        PiFactory.getPi("twotwoseven").run();

        PiFactory.getPi("threesevenseven").run();

        PiFactory.getPi("Iowa").run();

        PiFactory.getPi("sqrootIowa").run();

    }

}