Chapter 5, Problem 38CRP

The factorial of 0 is defined to be 1. The factorial of a positive integer is defined to be the product of that integer times the factorial of the next smaller nonnegative integer. We use the notation n! to express the factorial of the integer n. Thus the factorial of 3 (written 3!) is 3 × (2!) = 3 × (2 × (1!)) = 3 × (2 × (1 × (0!))) = 3 × (2 × (1 × (1))) = 6. Design a recursive algorithm that computes the factorial of a given value.