Calculate something more than a var can handle

[mitocondrio]

Let's say I want to calculate something like PI using some algorithm, but with the number of digits I want to. How can I do it?

[Stewbond]

If you want 32 bits of precision, use a float
If you want 64 bits of precision, use a double
If you want a larger amount of precision, use a big numbers library.
http://en.wikipedia.org/wiki/Arbitrary-precision_arithmetic