Java 6 Illuminated: An Active Learning Approach, 2nd Edition

13.2 Recursion with a Return Value 947

case argument receives its return value, which allows that method to return

a value to its caller, and so on, until the method is able to return a value to

the initial caller. In this way, the return values unravel up to the initial

caller.

To see how this works, let’s look at an example of a recursive method that

returns a value.

13.2.1 Computing the Factorial of a Number

We will define a recursive method to compute and return the factorial of a

positive integer.

The factorial of a positive number is defined as follows:

factorial(n) = n ! = n * (n  1) * (n  2) * (n  3) * ... .* 4 * 3 * 2 * 1

The factorial of