Factorials

Recursive computation of factorials

This example is a slight cliché, but it is still a good illustration of both the beauty and pitfalls of recursion.

The factorial of an integer, $n$, is the product of all the integers between $1$ and $n$. For example, six factorial (usually written $6!$) is:

$$6\ast 5\ast 4\ast 3$$ ...