How do you convert a string to ascii to binary in C#?

Question

A while back (freshman year of high school) I asked a really good C++ programmer who was a junior to make a simple application to convert a string to binary. He gave me the following code sample:

void ToBinary(char* str)
{
    char* tempstr;
    int k = 0;

    tempstr = new char[90];

    while (str[k] != '\0')
    {
        itoa((int)str[k], tempstr, 2);
        cout << "\n" << tempstr;
        k++;
    }

    delete[] tempstr;
}

So I guess my question is how do I get an equivalent to the itoa function in C#? Or if there is not one how could I achieve the same effect?

score 11 · Accepted Answer · answered Apr 10 '09 at 02:37

This is very easy to do with C#.

var str = "Hello world";

With LINQ
foreach (string letter in str.Select(c => Convert.ToString(c, 2)))
{
  Console.WriteLine(letter);
}

Pre-LINQ
foreach (char letter in str.ToCharArray())
{
  Console.WriteLine(Convert.ToString(letter, 2));
}

score 2 · Answer 2 · answered Apr 10 '09 at 02:32

2

Use an ASCIIEncoding class and call GetBytes passing the string.

answered Apr 10 '09 at 02:32

JP Alioto

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This doesn't seem to me to have anything to do with the question. I might be wrong, because the question is quite vague except for the somewhat odd sample code. – mqp Apr 10 '09 at 02:37
The code sample is a little odd but you should know what it does. It gets each char value and converts it to its binary representation and outputs it. – Samuel Apr 10 '09 at 02:38
Sorry, I didn't mean to be vague. This was just a hobby project I was working on. – Kredns Apr 10 '09 at 02:43

score 2 · Answer 3 · answered Apr 10 '09 at 02:34

It's not clear precisely what you want, but here's what I think you want:

return Convert.ToString(int.Parse(str), 2); // "5" --> "101"

This isn't what the C++ code does. For that, I suggest:

string[] binaryDigits = str.Select(c => Convert.ToString(c, 2));
foreach(string s in binaryDigits) Console.WriteLine(s);

score 1 · Answer 4 · edited Nov 08 '11 at 02:38

Thanks, this is great!! I've used it to encode query strings...

protected void Page_Load(object sender, EventArgs e)
{
    string page = "";
    int counter = 0;
    foreach (string s in Request.QueryString.AllKeys)
    {
        if (s != Request.QueryString.Keys[0])
        {
            page += s;
            page += "=" + BinaryCodec.encode(Request.QueryString[counter]);
        }
        else
        {
            page += Request.QueryString[0];
        }
        if (!page.Contains('?'))
        {
            page += "?";
        }
        else
        {
            page += "&";
        }
        counter++;
    }
    page = page.TrimEnd('?');
    page = page.TrimEnd('&');
    Response.Redirect(page);
}

public class BinaryCodec
{
    public static string encode(string ascii)
    {
        if (ascii == null)
        {
            return null;
        }
        else
        {
            char[] arrChars = ascii.ToCharArray();
            string binary = "";
            string divider = ".";
            foreach (char ch in arrChars)
            {
                binary += Convert.ToString(Convert.ToInt32(ch), 2) + divider;
            }
            return binary;
        }
    }

    public static string decode(string binary)
    {
        if (binary == null)
        {
            return null;
        }
        else
        {
            try
            {
                string[] arrStrings = binary.Trim('.').Split('.');
                string ascii = "";
                foreach (string s in arrStrings)
                {
                    ascii += Convert.ToChar(Convert.ToInt32(s, 2));
                }
                return ascii;
            }
            catch (FormatException)
            {
                throw new FormatException("SECURITY ALERT! You cannot access a page by entering its URL.");
            }
        }
    }
}

score 1 · Answer 5 · answered Jun 23 '16 at 21:58

Here's an extension function:

        public static string ToBinary(this string data, bool formatBits = false)
        {
            char[] buffer = new char[(((data.Length * 8) + (formatBits ? (data.Length - 1) : 0)))];
            int index = 0;
            for (int i = 0; i < data.Length; i++)
            {
                string binary = Convert.ToString(data[i], 2).PadLeft(8, '0');
                for (int j = 0; j < 8; j++)
                {
                    buffer[index] = binary[j];
                    index++;
                }
                if (formatBits && i < (data.Length - 1))
                {
                    buffer[index] = ' ';
                    index++;
                }
            }
            return new string(buffer);
        }

You can use it like:

Console.WriteLine("Testing".ToBinary());

which outputs:

01010100011001010111001101110100011010010110111001100111

and if you add 'true' as a parameter, it will automatically separate each binary sequence.

How do you convert a string to ascii to binary in C#?

5 Answers5

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