C# Convert large binary string to decimal system

Question

I\'ve got a large text, containing a number as a binary value. e.g \'123\' would be \'001100010011001000110011\'. EDIT: should be 1111011

Now I want to convert it to

Answer 1

This'll do the trick:

public string BinToDec(string value)
{
    // BigInteger can be found in the System.Numerics dll
    BigInteger res = 0;

    // I'm totally skipping error handling here
    foreach(char c in value)
    {
        res <<= 1;
        res += c == '1' ? 1 : 0;
    }

    return res.ToString();
}