using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var list = new List<double>();

        list.Add(0.32);

        list.Add(0.0);

        list.Add(-0.78);

        list.Add(-0.1);

        list.Add(0.25);

        list.Add(1.0);

        list.Add(0.84);

        list.Add(-1.0);

        list.Add(0.1);

        list.Sort((x,y) => Compare(x, y));

        foreach (var x in list)

            Console.WriteLine(x);

    }

    public static int Compare(double x, double y)

    {

        if (x >= 0.0 == y>=0.0)

            // same sign, compare by absolute value

            return Math.Abs(x).CompareTo(Math.Abs(y));

        if (x < 0.0)

            return 1;

        return -1;

    }

​

}