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

952 CHAPTER 13 Recursion

Figure 13.5

A Run of Example 13.2 if

the Base Case Is Not

Coded

Figure 13.5 shows a run of Example 13.2 (the RecursiveFactorial class) with

lines 20 to 22 commented out.

13.2.2 Computing the Greatest Common Divisor

A common algebra problem is to calculate the greatest common divisor, or

gcd, of two positive integers. The gcd is the greatest positive integer that

divides evenly into both numbers.

For example, consider 50 and 20. We can figure in our head that 5 divides

evenly into both numbers, but so does 10. Since we can’t find a number greater

than 10 that divides evenly into both numbers, 10 is the gcd of 50 and 20.

It is easy ...