How to store extremely large numbers?

Question

For example I have a factorial program that needs to save really huge integers that can be 50+ digits long. The absolute maximum primitive data type in C++ is unsigned

Answer 1

You'll have to use a bigint or bignum implementation. There are some libraries out there like this: http://gmplib.org/

Some more info and a list of libraries: http://en.wikipedia.org/wiki/Bignum