% Jake Bobowski
% July 27, 2017
% Created using MATLAB R2014a

% This tutorial will introduce simple implementations of while loops 
% in MATLAB.

clearvars

% Here's while loop that calculates the factorial of n.  Start with n = 4
% to make sure things are working properly.  The loop executes until n > 1.
% That is, the the last iteration of the loop will occur when n = 2. (You
% could actually let the while loop run until n = 1 since factorial*1 = 
% factorial). 
n = 4;
disp(['n = ' num2str(n)])
factorial = 1;
while n > 1
    factorial = factorial*n;
    n = n-1;
end
disp(['n! = ' num2str(factorial)])

% Here's a more interesting factorial
n = 150;
disp(['n = ' num2str(n)])
factorial = 1;
while n > 1
    factorial = factorial*n;
    n = n-1;
end
disp(['n! = ' num2str(factorial)])

% Maybe you want to the user to be able to enter only integer numbers.  See
% the nested control structure tutorial to see an implementation of this
% check.  That tutorial will also show you how to calculate the factorials
% of a bunch of n values and then plot the results vs n.