using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Text;
public class MainClass
{
public static void Main()
{
IList<double> myList = new List<double>();
myList.Add(10.5);
myList.Add(209.224);
myList.Insert(1, 3.999);
myList.Add(48.2);
myList.Remove(10.4);
Console.WriteLine("IndexOf {0} = {1}", 209.2234, myList.IndexOf(209.2234));
Console.WriteLine("IndexOf {0} = {1}", 10.54, myList.IndexOf(10.54));
}
}