How would you write a non-recursive algorithm to calculate factorials?

Question

How would you write a non-recursive algorithm to compute n!?

Answer 1

Unless you have arbitrary-length integers like in Python, I would store the precomputed values of factorial() in an array of about 20 longs, and use the argument n as the index. The rate of growth of n! is rather high, and computing 20! or 21! you'll get an overflow anyway, even on 64-bit machines.