c# - BigInteger Parse Octal String?

Question

In Java, I could do

//Parsing Octal String
BigInteger b = new BigInteger("16304103460644701340432043410021040424210140423204",8);

Then format it as I pleased

b.toString(2); //2 for binary
b.toString(10); //10 for decimal
b.toString(16); //16 for hexadecimal

C#'s BigInteger offers the formatting capabilities shown above but I can't seem to find a way to parse BIIIG (greater than 64 bit, unsigned) Octal values.

Answer 1

This may not be the most efficient solution, but if performance is not a priority, you can construct the BigInteger manually:

string s = "16304103460644701340432043410021040424210140423204";
BigInteger bi = s.Aggregate(new BigInteger(), (b, c) => b * 8 + c - '0');

The above solution also works for any base not greater than 10; just replace the 8 in the above code with your required base.

Edit: For hexadecimal numbers, you should use the Parse method. Prepend with 0 if your number should be interpreted as positive even if its first character is 8–F.

string s = "0F20051C5E45F4FD68F8E58905A133BCA";
BigInteger bi = BigInteger.Parse(s, NumberStyles.HexNumber);