Fisher's Exact Test for beginners.

A simple, fast and short code for beginners, who cares about Fisher's Exact Test, .
As a beginner, at least you need to know what we do with Fisher's Exact Test (see [1][2]). My function is simple,

Pvalue = FisherExactTest22(x,y)

Input: either 2*2 contigency table or two vectors,
Output: four p-values at, left tail , Right tail, 2-tails, and Mid-p correction for 2-tails .

Well, if you don't know anything about how to choose, as a beginner, I suggested you use 2-tails, that is : Pvalue(3)

Attention: if you have contigency table more complex to 2*2, refer to my another algorithm at :
http://www.mathworks.com/matlabcentral/fileexchange/24379-fishers-exact-test-with-n-x-m-contingency-table

Please start from "ControlCenter.m", two examples are there.
Let me know any question you have, I will try to response to you as soon as possible.

[1]http://mathworld.wolfram.com/FishersExactTest.html
[2]http://www.mathworks.com/matlabcentral/fileexchange/15434