Source code in the matlab programming language

 function notes(varargin)
    % NOTES can be used for taking notes 
    % usage:
    %    notes    displays the content of the file NOTES.TXT
    %    notes arg1 arg2 ... 
    %             add the current date, time and arg# to NOTES.TXT
    %

    filename = 'NOTES.TXT'; 
    if nargin==0
	fid = fopen(filename,'rt');
	if fid<0, return; end; 
	while ~feof(fid)
		fprintf('%s\n',fgetl(fid));
	end; 
	fclose(fid); 
    else
        fid = fopen(filename,'a+');
	if fid<0, error('cannot open %s\n',filename); end; 
        fprintf(fid, '%s\n\t%s', datestr(now),varargin{1});
        for k=2:length(varargin)
            fprintf(fid, ', %s', varargin{k});
	end; 
	fprintf(fid,'\n');
	fclose(fid);
    end;