Question

i’m just started dev-ing app for wp7 and I’m trying to convert a string of binary back to ascii using c#.

But i have no idea how can it be done.
Hope someone could help me out here.

example :

Input string: 0110100001100101011011000110110001101111

Output string: hello

Answer 1

The simple solution,

using SubString and built in Convert.ToByte could look like this:

string input = "0110100001100101011011000110110001101111";
int charCount = input.Length / 8;
var bytes = from idx in Enumerable.Range(0, charCount)
            let str = input.Substring(idx*8,8)
            select Convert.ToByte(str,2);
string result = Encoding.ASCII.GetString(bytes.ToArray());
Console.WriteLine(result);

Another solution, doing the calculations yourself:

I added this in case you wanted to know how the calculations should be performed, rather than which method in the framework does it for you:

string input = "0110100001100101011011000110110001101111";
var chars = input.Select((ch,idx) => new { ch, idx});
var parts = from x in chars
            group x by x.idx / 8 into g
            select g.Select(x => x.ch).ToArray();

var bytes = parts.Select(BitCharsToByte).ToArray();
Console.WriteLine(Encoding.ASCII.GetString(bytes));

Where BitCharsToByte does the conversion from a char[] to the corresponding byte:

byte BitCharsToByte(char[] bits) 
{
    int result = 0;
    int m = 1;
    for(int i = bits.Length - 1 ; i >= 0 ; i--) 
    {
        result += m * (bits[i] - '0');
        m*=2;
    }
    return (byte)result;
}

Both the above solutions does basically the same thing: First group the characters in groups of 8; then take that sub string, get the bits represented and calculate the byte value. Then use the ASCII Encoding to convert those bytes to a string.