using System;

​

public class Program

{

    public static void Main()

    {

                /*

        125 = 125  bytes

        1040 = 1.01 kb

        9999999 = 9.53 mb

​

        1024 bytes = 1 KB

        1024 KB = 1 MB

        1024 MB = 1 GB      

                */

        Console.WriteLine(GetReableFileSize(125));

        Console.WriteLine(GetReableFileSize(1040));

        Console.WriteLine(GetReableFileSize(9999999));

        Console.WriteLine(GetReableFileSize(1024));

        Console.WriteLine(GetReableFileSize(1024000));

        Console.WriteLine(GetReableFileSize(1024000000));

    }

​

    /// Returns Redable file size for input file size

    ///Program can return filesize till terabytes could be extened more 

    public static string GetReableFileSize(long inputSize)

    {

        long fileSize = (inputSize < 0 ? -inputSize : inputSize);

        // Determine the suffix and readable value

        string sizeSuffix;

        double readableSize;

        // Compare filesize in hex and use right shift opertor for binary operations

        if (fileSize >= 0x10000000000) // Terabyte

        {

            sizeSuffix = "TB";

            readableSize = (inputSize >> 30);

        }

        else if (fileSize >= 0x40000000) // Gigabyte

        {

            sizeSuffix = "GB";

            readableSize = (inputSize >> 20);

        }

        else if (fileSize >= 0x100000) // Megabyte

        {

            sizeSuffix = "MB";

            readableSize = (inputSize >> 10);

        }

        else if (fileSize >= 0x400) // Kilobyte

        {

            sizeSuffix = "KB";

            readableSize = inputSize;

        }

        else

        {

            return inputSize.ToString("0 Bytes"); // Byte

        }

​

        readableSize = (readableSize / 1024);

        return readableSize.ToString("0.### ") + sizeSuffix;

    }

}