Recursion implementation techniques

There are a few implementation issues that should be addressed. These include the use of wrapper methods and short-circuiting the base case. These techniques can assist in the use of recursion.

Using a wrapper method

A wrapper method is used to support recursion. This method will not actually perform recursion but will call one that does. The wrapper method may:

• Validate parameters

• Perform initialization

• Handle exceptions as errors are generated

The following is an example of a wrapper method for the arrayTotal method, which is duplicated here for your convenience:

    public int arrayTotal(int numbers[], int index) {
        if (index == 0) {
            return numbers[0];
        } else {
            return numbers[index] + arrayTotal(numbers, index - 1);
        }
    }

In the arrayTotalHelper method, the index variable is checked to see if it is within the bounds of the array. If it is not, then the exception needs to be handled:

    public int arrayTotalHelper...