Thursday Code Puzzler: Return the Factorial

Thursday is code puzzler day here at DZone. The idea is simple: solve the coding problem as efficiently as you can, in any language or framework that you find suitable.

Note: Even though there really is nothing stopping you from finding a solution to this on the internet, try to keep honest, and come up with your own answer.  It's all about the participation!

Return the Factorial

Write a function which will return the factorial of a number n. Factorial is the product of the sequence  n, n-1, n-2 .... 1.  And remember that the factorial of 0 is actually 1. 

Catch up on all our previous puzzlers here