using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public class number

    {

        public int num { get; set; }

    }

    public static void Main()

    {

        var numbers = new List<number>();

​

        numbers.Add( new number{ num = 1 } );

        numbers.Add( new number{ num = 2 } );

        numbers.ForEach( i => i.num *= 2 );

        foreach( var i in numbers )

        {

            Console.WriteLine( i.num );

        }

    }

}