Converting Back from Decimal to Byte - C# Discussion Boards

12-Feb-14 10:03

/*
First Phase:: I attempting to copy a file off my desktop into a byte array. Then transposing all the bytes into an equivalent decimal array. The decimal array is must (it is very important).

Second Phase:: I am attempting to convert the same decimal array back to a byte array and write the file back to the desktop or a folder or path. 

The first phase was accomplish with help from the forum, but the second gives me back a garbage file on the desktop. I was attempting to use WriteAllBytes, but I do not know how to use this method. Can you someone please assist me with "WriteAllBytes" or show simply show me how to stop getting garbage file?
*/
using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;
 
namespace Applica
{
    class Program
    {
        static void Main(string[] args)
        {
            long Totbyte = 0;
            string filePath = null;
            DirectoryInfo da = new DirectoryInfo("C:\\Folder");
            FileInfo[] Arr = da.GetFiles();
 
            foreach (FileInfo ap in Arr)
            {
                Totbyte = ap.Length;
                filePath = ap.FullName;
            }
            Console.WriteLine("Total Bytes = {0} bytes", Totbyte);
            string temPath = Path.GetTempFileName();
            byte[] data = new byte[Totbyte];
 
            if (File.Exists(temPath))
            {
                data = File.ReadAllBytes(filePath);
                File.WriteAllBytes(temPath, data);
            }
            decimal[] arry = new decimal[Totbyte];
            for (int count = 0; count < data.Length; count++)
            {
                arry[count] = data[count];
             //   Console.WriteLine("Byte to Decimal = {0},,,,,, count = {1}", arry[count], count);
            }
            ///////////ABOVE: READ IN FILE AND CHANGE EACH BYTE TO DECIMAL
            ///////////BELOW: TRYING TO REVERSE THE ABOVE PROCESS
            byte[] data2 = new byte[Totbyte];
            for (int count = 0; count < arry.Length; count++)
            {
                data2[count] = (byte)arry[count];
            }
            FileStream file = new FileStream(filePath, FileMode.Create);
            BinaryWriter binarystream = new BinaryWriter(file);
            binarystream.Write(data2);
            binarystream.Close();
        }
    }
}

Richard Deeming12-Feb-14 11:07

12-Feb-14 11:07

Firstly, why have you reposted this question when Harold is already helping you on your previous copy of this question[^]?

Secondly, the code you have posted does not produce a "garbage file". The bytes in data2 will match the bytes in data exactly. You will end up overwriting the original file with an exact copy of itself.

Thirdly, you state that you don't know how to use the File.WriteAllBytes method, and yet you have a perfectly valid example of it in your code!

Cleaning up your code, replacing the BinaryWriter with File.WriteAllBytes, and adding some sanity checks:

DirectoryInfo da = new DirectoryInfo("C:\\Folder");
FileInfo[] Arr = da.GetFiles();
if (Arr.Length == 0)
{
    throw new InvalidOperationException("No files found.");
}


// No need to loop through the array just to get the last item:
FileInfo ap = Arr[Arr.Length - 1];
long Totbyte = ap.Length;
string filePath = ap.FullName;
Console.WriteLine("Total Bytes = {0} bytes", Totbyte);


// GetTempFileName *creates* the file, so it always exists:
string temPath = Path.GetTempFileName();
byte[] data = File.ReadAllBytes(filePath);
File.WriteAllBytes(temPath, data);


// Convert the bytes to decimals:
decimal[] arry = new decimal[Totbyte];
for (int count = 0; count < data.Length; count++)
{
    arry[count] = data[count];
}


// Convert the decimals back to bytes:
byte[] data2 = new byte[Totbyte];
for (int count = 0; count < arry.Length; count++)
{
    data2[count] = (byte)arry[count];
}


// Just to prove they're the same:
if (data2.Length != data.Length)
{
    throw new InvalidOperationException("Wrong length!");
}
for (int index = 0; index < data.Length; index++)
{
    if (data[index] != data2[index])
    {
        throw new InvalidOperationException("Data has changed at index " + index);
    }
}


// Write the bytes back to the file:
File.WriteAllBytes(filePath, data2);


// To prove they're still the same:
data = File.ReadAllBytes(temPath);
data2 = File.ReadAllBytes(filePath);

if (data2.Length != data.Length)
{
    throw new InvalidOperationException("Wrong length!");
}
for (int index = 0; index < data.Length; index++)
{
    if (data[index] != data2[index])
    {
        throw new InvalidOperationException("Data has changed at index " + index);
    }
}

If you run this code and end up with a "garbage" file, that means you started with a garbage file!

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

computerpublic12-Feb-14 11:29

12-Feb-14 11:29

Can you put the new file in another directory so I can have two files to compare later? Or maybe just change the name so i can have two files to compare?

Richard Deeming13-Feb-14 0:37

13-Feb-14 0:37

Yes, you just need to change the path in your WriteAllBytes call:

// Write the bytes to a different file:
string filePath2 = Path.Combine("C:\\A Different Folder", Path.GetFileName(filePath));
File.WriteAllBytes(filePath2, data2);

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

computerpublic13-Feb-14 9:15

13-Feb-14 9:15

<pre>/*
IT DOESN'T WORK..I ADDED THE LINE:::string filePath2 = Path.Combine("C:\\check", Path.GetFileName(filePath));
I RAN THE PROGRAM AND CHECK FOLDER WAS EMPTY. THE FILE WAS NOT WRITTEN TO THE NEW LOCATION. ALL I WANT TO DO SEE ANOTHER INSTANCE OF THE FILE
*/

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Applica
{
    class Program
    {
        static void Main(string[] args)
        {
            DirectoryInfo da = new DirectoryInfo("C:\\Folder");
            FileInfo[] Arr = da.GetFiles();
            if (Arr.Length == 0)
            {
                throw new InvalidOperationException("No files found.");
            }
            // No need to loop through the array just to get the last item:
            FileInfo ap = Arr[Arr.Length - 1];
            long Totbyte = ap.Length;
            string filePath = ap.FullName;
            Console.WriteLine("Total Bytes = {0} bytes", Totbyte);
            // GetTempFileName *creates* the file, so it always exists:
            string temPath = Path.GetTempFileName();
            byte[] data = File.ReadAllBytes(filePath);
            File.WriteAllBytes(temPath, data);
            // Convert the bytes to decimals:
            decimal[] arry = new decimal[Totbyte];
            for (int count = 0; count < data.Length; count++)
            {
                arry[count] = data[count];
            }
            // Convert the decimals back to bytes:
            byte[] data2 = new byte[Totbyte];
            for (int count = 0; count < arry.Length; count++)
            {
                data2[count] = (byte)arry[count];
            }
            // Just to prove they're the same:
            if (data2.Length != data.Length)
            {
                throw new InvalidOperationException("Wrong length!");
            }
            for (int index = 0; index < data.Length; index++)
            {
                if (data[index] != data2[index])
                {
                    throw new InvalidOperationException("Data has changed at index " + index);
                }
            }
            // Write the bytes back to the file:
            string filePath2 = Path.Combine("C:\\check", Path.GetFileName(filePath));
            File.WriteAllBytes(filePath, data2);
            // To prove they're still the same:
            data = File.ReadAllBytes(temPath);
            data2 = File.ReadAllBytes(filePath);
            if (data2.Length != data.Length)
            {
                throw new InvalidOperationException("Wrong length!");
            }
            for (int index = 0; index < data.Length; index++)
            {
                if (data[index] != data2[index])
                {
                    throw new InvalidOperationException("Data has changed at index " + index);
                }
            }

        }
    }
}

Richard Deeming13-Feb-14 10:35

13-Feb-14 10:35

computerpublic wrote:
string filePath2 = Path.Combine("C:\\check", Path.GetFileName(filePath));
File.WriteAllBytes(filePath, data2);

If you want to write the bytes to the file whose path is stored in the filePath2 variable, then you need to pass that variable to the WriteAllBytes method, as I showed you in my previous answer[^].

// Write the bytes to a different file:
string filePath2 = Path.Combine("C:\\check", Path.GetFileName(filePath));
File.WriteAllBytes(filePath2, data2); // <-- NB: Pass filePath2 here, not filePath!

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

computerpublic13-Feb-14 10:48

13-Feb-14 10:48

It works. Thank you very much Richard.

computerpublic16-Feb-14 6:00

16-Feb-14 6:00

<pre>/*
I AM NOW TRYING TO CONVERT BYTE TO STRING AND ALSO CONVERTING BACK FROM STRING TO BYTE. 
I ALSO WANT TO SEE THE OUTPUT.
I AM NOT UNDERSTING WHY I AM GETTING AN ERROR.
THE OUTPUT INFORMATION IS BELOW::

Total Bytes = 8228730 bytes

Unhandled Exception: System.InvalidOperationException: Data has changed at index
 310
   at Applica.Program.Main(String[] args) in C:\Documents and Settings\shampro\D
esktop\Program.cs:line 41
Press any key to continue . . .
*/

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Applica
{
    class Program
    {
        static void Main(string[] args)
        {
            DirectoryInfo da = new DirectoryInfo("C:\\Folder");
            FileInfo[] Arr = da.GetFiles();
            if (Arr.Length == 0)
            {
                throw new InvalidOperationException("No files found.");
            }
            // No need to loop through the array just to get the last item:
            FileInfo ap = Arr[Arr.Length - 1];
            long Totbyte = ap.Length;
            string filePath = ap.FullName;
            Console.WriteLine("Total Bytes = {0} bytes", Totbyte);
            // GetTempFileName *creates* the file, so it always exists:
            string temPath = Path.GetTempFileName();
            byte[] data = File.ReadAllBytes(filePath);
            File.WriteAllBytes(temPath, data);
            // Convert the bytes to string:
            string arry = ASCIIEncoding.ASCII.GetString(data);
            Console.WriteLine(arry);
            // Convert the string back to bytes:
            byte[] data2 = Encoding.ASCII.GetBytes(arry);
            foreach (byte element in data2)
            {
                Console.WriteLine("{0}={1}",element ,(char)element);
            }
            // Just to prove they're the same:
            if (data2.Length != data.Length)
            {
                throw new InvalidOperationException("Wrong length!");
            }
            for (int index = 0; index < data.Length; index++)
            {
                if (data[index] != data2[index])
                {
                    throw new InvalidOperationException("Data has changed at index " + index);
                }
            }
            // Write the bytes back to the file:
            string filePath2 = Path.Combine("C:\\check", Path.GetFileName(filePath));
            File.WriteAllBytes(filePath2, data2);
            // To prove they're still the same:
            data = File.ReadAllBytes(temPath);
            data2 = File.ReadAllBytes(filePath);
            if (data2.Length != data.Length)
            {
                throw new InvalidOperationException("Wrong length!");
            }
            for (int index = 0; index < data.Length; index++)
            {
                if (data[index] != data2[index])
                {
                    throw new InvalidOperationException("Data has changed at index " + index);
                }
            }

        }
    }
}

computerpublic16-Feb-14 6:03

16-Feb-14 6:03

SORRY, THE PROBLEM IS ON LINE 61. BEFORE THE PROBLEM WAS ON LINE 41, BUT I ADDED COMMENTS AND SHIFTED THE ENTIRE THING DOWN.

Richard Deeming17-Feb-14 1:46

17-Feb-14 1:46

Hardly surprising - ASCII encoding can only cope with 128 characters. If any of your bytes are greater than or equal to 128, the ASCIIEncoding class[^] will replace them with a question mark. When you re-encode the string, these bytes will have been replaced with the value 63.

You still haven't explained what you're trying to achieve.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

computerpublic18-Feb-14 22:51

18-Feb-14 22:51

I am trying to become a good programmer, but following the examples in the books sometimes does not work. The professor in the school is also very suspicious. I think she is reading the chapters before the class and pretending like she knows. She never answers direct questions. The answer always come in the next class session. I feel I am on my own with c#. Sometimes I feel that the people who write the books, don't know any c# at all. How it is possible for examples in text not to work. I encounter this problem many times and it is very frustrating. To add to the frustration, I go online to the help forums and I continually being ask "What are you trying to achieve"? As if a non programmer is not allowed to ask questions and learn from people who know. I am trying to learn from people who know, that is what I am trying to achieve. I hope this answers the question.

computerpublic18-Feb-14 23:03

18-Feb-14 23:03

Could you please kindly respond to my new post "Out Of Memory Exception"? It is a completely different question, so I didn't thought it wise to post it here. Thank You.

Richard Deeming19-Feb-14 1:59

Re: Converting Back from Bit to Byte

19-Feb-14 1:59

computerpublic wrote:
I continually being ask "What are you trying to achieve"? As if a non programmer is not allowed to ask questions and learn from people who know.

We don't ask what you're trying to achieve because we don't want you asking questions; it's just that, if you tell us what you want the code to do, we might be able to point you towards a better solution. It's often better to take a step back and look at the bigger picture of what you want to do, rather than fixating on why a particular line of code doesn't do what you expect. Smile | :)

Your professor certainly doesn't sound like she's up to the job. Have you tried talking to your tutor about your concerns?

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

computerpublic13-Mar-14 8:16

13-Mar-14 8:16

<pre>/*If I am generating a series of bits ONE BIT AT A TIME for example {10101000}. How do I turn the entire series into one byte after I generate the 8th bit. I am trying to back track using the example you gave me, but I am getting some errors.*/

using System;
using System.IO;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Applica
{
    class Program
    {
        static Random _random = new Random ();////Start: Fisher-Yates Array Shuffler
        public static void Shuffle<T>(T[] array)
        {
            var random = _random;
            for (int i = array.Length; i > 1; i--)
            {
                int j = random.Next(i);
                T tmp = array[j];
                array[j] = array[i - 1];
                array[i - 1] = tmp;
            }
        }////////////////////////////////////////////End: Fisher-Yates Array Shuffer
        static void Main(string[] args)
        {
            byte[] outdata = new byte[1];
            BitArray[] bits2 = new BitArray[8];
            char[] array = {'1','0','1','0','1','0','1','0'};
            Shuffle(array);
            for (int i = 0; i < 8; i++)
                bits2[i] = array[1];//Error: Cannot Implicitly convert type 'char' to 'System.Collections.BitArray'
            outdata[i] = (byte)bits2;//Error: Cannot convert type 'System.Collections.BitArray[]' to 'byte' 
        }
    }
}

Eddy Vluggen12-Feb-14 11:21

Eddy Vluggen

12-Feb-14 11:21

~~Totbyte isn't set in your version and remains 0. Had you not initialized the variable with 0 then the compiler would have warned you.~~
Tis set. To the size of the last file in the folder.

D'Oh! | :doh:

..off for some Sleepy | :zzz:

Bastard Programmer from Hell Suspicious | :suss:

If you can't read my code, try converting it here[^]