using System; 

using System.Threading.Tasks;

using System.Collections.Generic;

​

public class Test { 

    public static int fab(int A) 

    { 

        return A + 10;

    }

    public static List<int> parMap(List<int> la, Func<int, int> fab) 

    {

        var result = new List<int>();

        foreach (var item in la)

        {

            Task<int> task = Task.Run(() => 

            {

                return fab(item);

            });

            result.Add(task.Result);

        }

        return result;

    }

    // Main Method 

    static public void Main() 

    { 

        var la = new List<int>() {1, 2, 3, 4, 5};

        var lb = new List<int>();

        lb = parMap(la, fab);

        Console.WriteLine("Origin list:");

        foreach (var item in la)

        {

            Console.Write(item + " ");

        }

        Console.WriteLine(Environment.NewLine + "New list:");

        foreach (var item in lb)

        {

            Console.Write(item + " ");

        }

    } 

}