function istr = paddednum2str(i) 
% checks length of string is two characters long & if not
% pads with a zero. Used to get days and months of 2 characters 
istr = num2str(i);
if length(istr) == 1
    istr = ['0' istr];
end;
if length(istr) ~= 2
    disp('Problem with paddednum2str')
end;
