BigInteger division in C#

Question

I am writing a class which needs accurate division of the BigInteger class in C#.

Example:

BigInteger x = BigInteger.Parse("1000000000000000000000000000000000000000000000000000000000000000000000000000000000000");
BigInteger y = BigInteger.Parse("2000000000000000000000000000000000000000000000000000000000000000000000000000000000000");

x /= y;

Console.WriteLine(x.ToString());

//Output = 0

The problem is that being an Integer, naturally it does not hold decimal values. How can I overcome this to get the real result of 0.5 (given example).

P.S. The solution must be able to accurately divide any BigInteger, not just the example!

Answer 1

What accuracy you need for the division? One way would be:

• Multiply the numerator by, say, 1000
• Divide the numbers
• Convert the result to double and divide by 1000

The same in code:

BigInteger x = BigInteger.Parse("1000000000000000000000000000000000000000000000000000000000000000000000000000000000000");
BigInteger y = BigInteger.Parse("2000000000000000000000000000000000000000000000000000000000000000000000000000000000000");

x *= 1000;
x /= y;
double result = (double)x;
result /= 1000;
Console.WriteLine(result);