using System;
using System.Globalization;
using System.Linq;

public class Test
{
	public static void Main()
	{
	       double d1 = 1d;
           double d2 = 0.2423423d;
           double d3 = 0.1d;
           double d4 = 1234d;
           double d5 = 1.234d;
           var culture = CultureInfo.CurrentCulture;
            var customNfi = (NumberFormatInfo)culture.NumberFormat.Clone();
            customNfi.NumberDecimalDigits = 1;
            customNfi.NumberGroupSeparator = "";
           Console.WriteLine(d1.ToString(customNfi));
           Console.WriteLine(d2.ToString(customNfi));
           Console.WriteLine(d3.ToString(customNfi));
           Console.WriteLine(d4.ToString(customNfi));
           Console.WriteLine(d5.ToString(customNfi));
	}
}