Solutions of Quiz 1 in Understandig ROS Topics in "ROS in 5 days"

I submitted my quiz, but I got 7/10 three times. Then, I check the solution code. My logic is the same with the solution code except that the solution code designed for 0.3 m left/right distance instead of 1 m. So, the solution code is wrong. Is it possible for me to resubmit after you correct it. I am also wondering if it is possible to get more detail about evaluation to see my mistakes.


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Welcome to the Community!

Could you please tell us the Quiz you are referring to? Which course and which unit?

In the meantime…

We normally don’t allow a retry of the quizzes or exams after the solution file is viewed. When you had a problem with grading, you should have contacted us rather than viewing the solution.

I really doubt that the problem was the distance moved, and we are working on providing more detailed feedback for what worked or didn’t work.

Awiating your feedback.

Thanks for quick your response. I changed the tittle based on you response. I will try to do better in the next quizzes.
For the feedback, I need to first understand the evaluation process. It seems that the test is similar to unit testing. I am wondering what are the criteria to determine the score. Could we see expected output and our output for the same simulation environment?

You’re welcome.

We evaluate the criteria set out in the exam. We compile and run your package in a sandbox environment, testing for the set out criteria. The grader expects specific file names, which is why we ask you to name and structure your package in a specific way.

Typical points of failure are:

  • The package did not compile.
  • A custom message or service or action was not compiled because it was not setup.
  • A file was not found because it was not named as expected.
  • The code the not give the expected output.

We try to give as much detail as possible in the grader output. But if you are still unclear about anything you can contact us to dig a little deeper by examining the logs.


I had this exact issue in the C++ class but it would not let me view the Solution, could someone please share the solution with me?

You can view the solution after submitting the quiz. Once you have viewed the solution once, you cannot submit again (and therefore cannot view the solution again).

Yeah I did submit the quiz and have a view of the answer. But I forget the answer now and I want to see it again. Could you please send me the answer. Thank you

You can submit again now. After the grader is done you will be able to check the solution again. Please note that you cannot directly “save” the solution page.