And now...: Recursion

(for more information, see here)

So now onto the recursion post.

Recursion is a process which repeats in a self-similar way. A recursive function calls itself within its definition to achieve the desired result. To prevent the program from falling into an infinitely deep hole, the function will do something else in a few specific cases. It is appropriate to use a recursive approach to solve a problem if the problem can be easier solved by solving smaller versions of the same problem. For example, with a three-peg Tower of Hanoi problem, if the programer recognizes that to move n disks from one peg to the next he must move n-1 disks to a third peg, then it becomes obvious that a recursive approach will be useful, since the solution involves solving problems smaller in scale. Recursion is a deceptively simple concept that makes it easy to solve potentially very complicated problems, although one that can be quite frustrating to trace and de-bug if something goes wrong!