Converting a binary string to BigInteger-CodePudding

I'm trying to convert a large binary string to a BigInteger number in C#. After doing some research a line such as the one below should work but for the 2 reasons below it isn't. Am I missing something?

BigInteger bi = new BigInteger("100101000111111110000", 2);

Error CS1503 Argument 1: cannot convert from 'string' to 'System.ReadOnlySpan'

Error CS1503 Argument 2: cannot convert from 'int' to 'bool'

CodePudding user response：

You can try Linq and get the result via Aggregate:

using.System.Linq;

...

BigInteger bi = "100101000111111110000"
  .Aggregate(BigInteger.Zero, (s, a) => (s << 1)   a - '0');

CodePudding user response：

The documentation for BigInteger show the different constructors.

But none of those constructors take a string and then an int as parameters. That's what the errors are about. Where did you get the idea the constructor took those arguments?

From what I could see, BigInteger cannot be called this way.

CodePudding user response：

 BigInteger bi = (BigInteger) 1341231.8523;

The above would cast your double to a decimal. However, the BigInteger Struct does not have functionality to convert from binary to integer. It looks like you used the BigInteger Java class functionality.

CodePudding user response：

This BigInteger belongs to Org.BouncyCastle.Math namespace in BouncyCastle.Crypto assembly.

Install it via NuGet (or in visual studio via NuGet manager)

Install-Package Portable.BouncyCastle -Version 1.9.0

Usage (convert a binary string to decimal)

var bi = new Org.BouncyCastle.Math.BigInteger("100101000111111110000", 2);
var decimalString = bi.ToString();
var b = double.TryParse(decimalString, out double d);