function letmat=letter(index,varargin)
% LETMAT=letter(index)    
% LETMAT=letter(index,1)
% This last option returns upper case
%
% Gives letters of the alphabet in a vector of strings
%
% Last modified by fjsimons-at-alum.mit.edu, June 28th, 2004

allc=97:122;
allup=65:90;

if nargin>1 & varargin{1}==1  
  letmat=str2mat(allup(index));
else
  letmat=str2mat(allc(index));
end