%
%  Provides MATLAB practice by reading commands from
%
disp('Welcome to the COEN 45 tutor.');
disp('Practice problems are taken from practice.m which you can change.')
disp('Only questions with one-line responses will work.')
disp('Type "error" (without the quotes) if you expect an error.')
disp('');
pause(2)
practice_script = 'practice.m';
[fid,message] = fopen(practice_script);
error(message);
praise = 'Good work!';
command = fgetl(fid);
%
%  "command" will be -1 at end-of-file
%
while ischar(command)
    %
    %  skip comments
    %
    while strcmp(command(1),'%') | isempty(command)
        command = fgetl(fid);
    end
    disp(command);
    if findstr(command,'pause')
        response = input('What will MATLAB display?\n','s');
        try
            matlab = evalc(command);
        catch
            matlab = 'error';
        end
        neq = findstr(matlab,'=');
        if ~isempty(neq)
            matlab = matlab(neq+1:end);
        end
        response(find(isspace(response))) = [];
        neq = findstr(response,'=');
        if ~isempty(neq)
            response = response(neq+1:end);
        end
        raw = matlab;
        matlab(find(isspace(matlab))) = [];
        while ~strcmp(response,matlab)
            response = input('Sorry, try again or ? to give up\n','s')
            giveup = strcmp(response(1),'?');
            if giveup
                disp(raw)
                praise = [];
                break
            else
                response(find(isspace(response))) = [];
                neq = findstr(response,'=');
                if ~isempty(neq)
                    response = response(neq+1:end);
                end
                praise = 'Good work!';
            end
        end
        disp(praise)
        praise = 'Good Work!';
        pause(0.5)
    else
        eval(command);
    end
    command = fgetl(fid);
end