Java™ How to Program, Seventh Edition

15.2. Recursion Concepts

Recursive problem-solving approaches have a number of elements in common. When a recursive method is called to solve a problem, the method actually is capable of solving only the simplest case(s), or base case(s). If the method is called with a base case, the method returns a result. If the method is called with a more complex problem, the method typically divides the problem into two conceptual pieces—a piece that the method knows how to do and a piece that it does not know how to do. To make recursion feasible, the latter piece must resemble the original problem, but be a slightly simpler or smaller version of it. Because this new problem looks like the original problem, the method calls a fresh copy of itself to work ...