C# High double precision

Question

I\'m writing a function that calculates the value of PI, and returns it as a double. So far so good. But once the function gets to 14 digits after the decimal place, it can\

Answer 1

How much precision do you need?

Using decimal will give you roughly 28 decimal places:

decimal pi = 3.14159265358979323846264338327950288419716939937510m;
Console.WriteLine(pi);    // 3.1415926535897932384626433833

If that's not enough for you then you'll need to search for some sort of BigDecimal implementation, or look at other techniques for performing the calculation.