gistfile1.txt

using System;
using System.Globalization;
using System.Runtime.CompilerServices;

class Program
{
    static void Main()
    {
        var val = GetValue();
        // DoubleConverter is from http://jonskeet.uk/csharp/DoubleConverter.cs
        Console.WriteLine(DoubleConverter.ToExactString(val));
        // 392.69999999999998863131622783839702606201171875
    }
    [MethodImpl(MethodImplOptions.NoInlining)]
    static double GetValue()
    {
        return 392.7;
    }
}