using System;

​

public interface ISeries<T>

{

    T GetNext();

    void Reset();

    void SetStart(T v);

}

​

class ByTwos<T> : ISeries<T>

{

    T start;

    T val;

    public delegate T IncByTwo(T v);

​

    IncByTwo incr; //сылка на делегат

    //консутруктор

    public ByTwos(IncByTwo incrMeth)

    {

        start = default(T);

        val = default(T);

        incr = incrMeth;

    }

    public T GetNext()

    {

        val = incr(val);

        return val;

    }

    public void Reset()

    {

        val = start;

    }

    public void SetStart(T v)

    {

        start = v;  

        val = start;

    }       

}

​

class ThreeD

{

    public int x, y, z;

    public ThreeD(int a,int b, int c)

    {

        x = a;

        y = b;

        z = c;

    }

}

​

public class Program

{

    static int IntPlusTwo(int v)

    {

        return v + 2;

    }

    static double IntPlusTwo(double v)

    {

        return v + 2.0;

    }

    static ThreeD ThreesPlus(ThreeD v)

    {

        if (v == null) return new ThreeD(0, 0, 0);

        else return new ThreeD(v.x + 2, v.y + 2, v.z + 2);

    }

    public static void Main()

    {

        Console.WriteLine("Hello World");

    }

}