Recursion and Cell Phones

Recursion is like having your cell phone forward to itself, then calling yourself.

Got it?

If you’re not a Comp Sci major, you’ve probably never heard of recursion. The simplest way to understand it is to look at some simple Visual Basic code that performs a factorial calculation. First, let’s take a look at how recursion is defined:

Start out with some natural number N (in our example, 5)
The factorial of N is N * N-1…until N=1.

So, if we let N be 5, then 5! is 5*4!. Now, we “recurse”, letting N be 4. So 4! is 4*3!. So 5! = 5*4*3!. (I know most are probably lost now. We started out with 5 factorial, and then let 5 factorial equal 5*4 factorial. We then let 5 factorial equal 5*4*3 factorial, by repeatedly applying the recursive definition of factorial.) So, 3! is 3*2!, 2! is 2*1!, 1! is 1*0!, and 0! is defined to equal 1. So,

5! = 5*4! = 5*4*3! = 5*4*3*2! = 5*4*3*2*1! = 5*4*3*2*1*0! = 5*4*3*2*1*1

Here’s the code snippet:

Isn’t that cool? So what it is it good for? Absolutely nothing. It’s a resource hog and loads up the call stack, but from a theoretical perspective it’s really cool (occasionally there are practical applications as well - very infrequent in web programming). There are entire languages (Scheme) built around recursion.

Cell phone has become most convenient source of communication. A large variety of cellular cell phones is available in market; especially variety of lg cell phone is rocking in market. You can also find used cell phones with low prices in market.

It can stretch your mind.  

As far as cell phones go. It didn’t work.