using System;

​

public interface Value

{

  string ToString();

}

​

public class Number : Value

{

    private int n;

    public Number(int _n)

    {

        n = _n;

    }

    public override string ToString()

    {

        return "Number: " + n.ToString();

    }

}

public interface IGenerator {}

public abstract class Generator<T> : IGenerator

{

    public int Columns { get; private set; }

    public int Rows { get; private set; }

    public Generator(int columns, int rows)

    {

        Columns = columns;

        Rows = rows;

    }

    public abstract T GetValue();

}

​

public class NumberGenerator : Generator<Number>

{

    public NumberGenerator(int columns, int rows) : base(columns, rows)

    {

    }

    public override Number GetValue()

    {

        return new Number(Columns * Rows);

    }

}

​

public static class Factory

{

    public static T GetGenerator<T>(params object[] args) where T : IGenerator

    {

        return (T)Activator.CreateInstance(typeof(T), args);

    }

}

​

public class Program

{

    public static void Main()

    {

        var gen = Factory.GetGenerator<NumberGenerator>(5,5);

        Number n = gen.GetValue();

        Console.WriteLine(n.ToString());

    }

}