using System;
using System.Linq;
using System.Collections.Generic;
class Program
{
static void Main() {
var list = new List<object> {3.14, -5.31, "c#", 8.18, "c", -99.17, 10, "c++", -5, -0.19};
List<double> result = list.OfType<double>().Where(d => d < 0).ToList();
Console.WriteLine(String.Join(", ", result));
}
}
/*
run:
-5.31, -99.17, -0.19
*/