How to implement a Matlab code that choose from random questions?

Hello everyone,

I was planning to implement a code in Matlab that generates a test. I have the questions and the answers and I would like the student to choose the correct answer, for each question, between 'a', 'b' and 'c'.

In short, I have a database of questions and solutions and I would like to generate a quiz with 30 questions randomly.

Thanks!

Answer 1

[Ameer Hamza]

You can use randperm() to generate a sequence of random numbers without repetition. For example, if you have a database of 100 questions and you want to choose 30 at random, you can do it like this

idx = randperm(100, 30);

'idx' will give the question number (out of 100) to include in a test.

[Leonardo Molino]

Thank you for you answer!

I would like to do this in Matlab.

I would like to create a set of questions that have multiple choices, so that the student can take the test and then Matlab comes back with results.

Questions must be chosen randomly from a database.

[Ameer Hamza]

In which form do you currently have the database of questions?

[Leonardo Molino]

It's a simple .txt

[Steven Lord]

Can you post two or three sample questions as they would be formatted in the file, so we can get a sense of the format and how best to read that information into MATLAB? Or can you attach a file (using the paperclip icon in the Insert section of the toolbar) with two or three files as they would be written in the text file?

[Leonardo Molino]

Sure.

***

Question #1. TITLE OF THE QUESTION HERE.

A - ANSWER HERE

B - ANSWER HERE

C- ANSWER HERE

***

Something like that

Answer 2

[Image Analyst]

Try this:

fullFileName = fullfile(pwd, 'Questions.txt');
if ~isfile(fullFileName)
	% Didn't find file.  Alert user.
	errorMessage = sprintf('Error: %s does not exist.', fullFileName);
	uiwait(warndlg(errorMessage));
	return;
end
% Open the file for reading in text mode.
fileID = fopen(fullFileName, 'rt');
% Read the first line of the file.
textLine = fgetl(fileID);
lineCounter = 1;
questions{lineCounter} = textLine;
while ischar(textLine)
	% Print out what line we're operating on.
	fprintf('%s\n', textLine);
	% Read the next line.
	textLine = fgetl(fileID);
	lineCounter = lineCounter + 1;
	if ischar(textLine) 
		questions{lineCounter} = textLine;
	end
end
% All done reading all lines, so close the file.
fclose(fileID);

numQuestions = length(questions)
randomOrder = randperm(numQuestions)
numQuestionsToAsk = 2;
for k = 1 : numQuestionsToAsk
	thisQuestionNumber = randomOrder(k);
	promptMessage = questions{thisQuestionNumber};
	titleBarCaption = 'Continue?';
	buttonText = questdlg(promptMessage, titleBarCaption, 'A', 'B', 'C', 'A')
end

Change the attached file to put in whatever questions you want.

[Leonardo Molino]

Thank you!

It's not homework, it's my idea to help a friend pass her psychology test!

[Image Analyst]

So did it work? If you want you can read the options in from the file and pass those strings to questdlg() instead of 'A', 'B', and 'C'.

[Leonardo Molino]

The code works very fine, thanks.

I'm trying to figure out how to implement a code that also checks if the entered answer is the correct one.

[Image Analyst]

Make a cell array of letters with the correct answers, like

answers = {'A', 'B', 'A', 'C'};

Then see if the response matches:

if strcmpi(buttonText, answers{k})
    % A correct response was selected.
else
    % An incorrect response was selected.
end

[Leonardo Molino]

Thank you!

I will try and I will let you know!