using System;

public class Program

{

    public static void Main()

    {

        var val = 0;

        Console.WriteLine("FileSize: {0}\t->\t{1}", val, FileSizeHelper.GetSize(val));

    }

}

​

public static class FileSizeHelper

{

    private const decimal KB = 1024M;

    private const decimal MB = 1048576M;

    private const decimal GB = 1073741824M;

    private const decimal TB = 1099511627776M;

​

    public static string GetSize(long bytesSize)

    {

        if(bytesSize <= 0) { return "0 B"; }

​

        var suffix = "B";

        var size = 0M;

​

        if (bytesSize >= TB) { size = bytesSize / TB; suffix = "TB"; }

        else if (bytesSize >= GB) { size = bytesSize / GB; suffix = "GB"; }

        else if (bytesSize >= MB) { size = bytesSize / MB; suffix = "MB"; }

        else if (bytesSize >= KB) { size = bytesSize / KB; suffix = "KB"; }

        else { size = bytesSize; suffix = "B"; }

​

        size = PrecisionHelper.Truncate(size, 2);

​

        return $"{size} {suffix}";

    }

}

​

public static class PrecisionHelper

{

    public static decimal Truncate(decimal value, int precision)

    {

        decimal step = (decimal)Math.Pow(10, precision);

        decimal temp = Math.Truncate(step * value);

​

        return temp / step;

    }

​

    public static double Truncate(double value, int precision)

    {

        double step = Math.Pow(10, precision);

        double temp = Math.Truncate(step * value);

​

        return temp / step;

    }

​

    public static double PrecisionStep(int precision)

    {

        double step = Math.Pow(10, precision);

        double temp = 1 / step;

​

        return temp;

    }

}