How to use Unsigned 256 bit integers(uint256) in C#

Question

Hello!

I wonder how it would be possible to calculate using Unsigned 256 bit integers(uint256) in C#, Visual Studio 2019.
(A uint256 variable has a maximum value of Math.Pos(2,256) – 1)

I have looked at BigInteger but are not sure if this can be used somehow or if I need to use another solution or library of some sort?
The image shows code that is written in solidity and in that language it is possible to use uint256.

I have written down an example calculation which is my goal to do in C# somehow. I have just put uint256 as declaration to illustrate what I am trying to do.

How can we calculate this in C#?
It would be needed to show a working example of the below calculation exactly because if I change uint256 to BigInteger I get compile error on line 10 that says:
Operator '/' cannot be applied to operands of type 'BigInteger' and 'double'

I am not sure if this is possible either to do and that bigdouble5 return the correct number?
double bigdouble5 = Math.Pow(2, 128)

Thank you!

                                    uint256 bigint1 = 329974300448100608374211110737048701521;  
                                    uint256 bigint2 = 326010339881230390929338722651861109232;  
                                    uint256 bigint3 = 92097159224555409225;  
                                    int decimals = 18;  
                                    uint256 bigint4 = bigint1 - bigint2;  
  
                                    double bigdouble5 = Math.Pow(2, 128); //returns very large number  
                                    double bigdouble6 = Math.Pow(10, decimals);  
  
                                    double NUM = ((bigint4 - 0) / bigdouble5) * bigint3 / bigdouble6; //Returns a normal double value like: "0.8654" (this it not the correct result though)  

Parts of original code from Solidity that I try to put in C#

Answer 1

I did this quick test with BigInteger, ... but not 100% sure with all those big numbers... =>

System.Numerics.BigInteger bigint1 = System.Numerics.BigInteger.Parse("329974300448100608374211110737048701521");
System.Numerics.BigInteger bigint2 = System.Numerics.BigInteger.Parse("326010339881230390929338722651861109232");
System.Numerics.BigInteger bigint3 = System.Numerics.BigInteger.Parse("92097159224555409225");
int decimals = 18;
System.Numerics.BigInteger bigint4 = bigint1 - bigint2;

System.Numerics.BigInteger bigint5 = System.Numerics.BigInteger.Pow(2, 128); //returns very large number
System.Numerics.BigInteger bigint6 = System.Numerics.BigInteger.Pow(10, decimals);

double nDiv = Math.Exp(System.Numerics.BigInteger.Log(bigint4) - System.Numerics.BigInteger.Log(bigint5));
double nResult = (double)(nDiv * (double)bigint3) / (double)bigint6;

Answer 2

Hi. I used this code to get the maximum value of Unsigned 256.

The value max has the correct value of 115792089237316195423570985008687907853269984665640564039457584007913129639935

byte[] bytes = new byte[] {
255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255, 255
};
BigInteger max = new BigInteger(bytes, true);