LAB 06 Tracing Algorithms; using Sub-Algorithms

EECS 1012: LAB 06 Tracing Algorithms; using Sub-Algorithms
A. REMINDERS
1) You should attend your own lab session (the one you are enrolled in). If you need to change your lab
enrollment, you should go to the department. Instructors or TAs cannot change your enrollment. TAs are
available via Zoom to help you during your lab hours.
2) You are required to pass the pre-lab mini quiz posted on eClass not later than the first 10 minutes of your
lab time. You should study the recent course materials and corresponding links/hints and Section B of this
document, as well as working on at least first tasks of this lab before trying the prelab quiz. You have 4
attempts; and you need at least 80% to pass. However, each time you may get some different questions.
You should try your first attempt at least one day before your deadline so that, if needed, you have time to
(re)study the materials for your next attempts. Failing the pre-lab mini quiz is equal to failing the whole lab,
yet you are still highly encouraged to complete the lab and submit your work to eClass.
3) You can also have your work verified and graded during the lab sessions. Feel free to signal a TA for help if
you stuck on any of the steps below. Yet, note that TAs would need to help other students too.
4) You can submit your lab work in eClass any time before 21:00 on Wednesday of the week the lab is for. In
order to pass this lab, your grade in it should be at least 70%.
B. IMPORTANT PRE-LAB WORKS YOU NEED TO DO BEFORE GOING TO THE LAB
1) Download this lab files and read them carefully to the end.
2) Practice tracing algorithms with different sample inputs. There are several examples in Lect06-ct3.
3) In Slides 23 and 24 of Lect06-ct3 notes, there is an example of sub-algorithm. Review it and implement it in
JavaScript once with and once without using sub-algorithms.
C. GOALS/OUTCOMES FOR LAB
• To practice computational thinking by first drawing flowcharts for basic computation
problems, verify if they are correct (by tracing them), then implement them in JS.
D. TASKS
1) Your first task in this lab is to verify 5 algorithms, in Exercises 1 to 5, by tracing them for some sample inputs.
You also provide pre- and post- conditions for each algorithm. In Exercise 6, you draw a flowchart that
includes two sub-algorithms. These tasks must be done in teams of two. (By the permission of the TA, only
one team can be in team of three if the lab population is odd.) While you are done, you should show your
trace tables, pre- and post- conditions for all flowcharts, as well as yor solution to Exercise 6 to your TAs
before you go to the next part. The TA may ask you to make minor modifications to demonstrate your
computational thinking skills in those contexts. Do NOT open VS-Code or browsers before finishing Task 1.
1) In Part 2, you implement all 6 exercises in JavaScript. You should create one html, one css, and one js file for
all your work, and you demo it to the TA. See next pages for further instructions.
E. SUBMISSIONS
1) Manual verification by a TA
You may want to have your TA verifying your lab before submission. The TA will look at your various files in
their progression. The TA may also ask you to make minor modifications to the lab to demonstrate your
knowledge of the materials. The TA can then record your grade in the system.
2) eClass submission
You will see an assignment submission link on eClass. Create a folder named “Lab06” and copy all your lab
materials inside (img_{01,02,03,04,05,06}.jpg, Lab06<yourName>.html,
Lab06<yourName>.css and Lab06<yourName>.js). This folder should be compressed (zip or or tar.gz)
and the compressed file submitted.
F. COMPUTATIONAL THINKIG
Part 1: This part must be done in teams of two. (By the permission of the TA, only one team can be in team of
three if the lab population is odd.) If you have done it at home, you are required to discuss it with a peer from
your lab before you show your final solution to your TA.
In Exercises 1 to 5, you verify the correctness of all algorithms by tracing them with some sample inputs. If an
algorithm ends without using all inputs, re-run it for the remaining inputs. You also write pre- and post- conditions
for each algorithm. In Exercise 6, you devise an algorithm that calls two sub-algorithms. In that Exercise you trace
your new sub-algorithms for some sample inputs. Note that terms algorithm, sub-algorithm, function, method,
programs are used interchangeably, yet they have subtle differences.
For each exercise, take one picture of all your trace tables and pre- post- conditions, including your name. By end of
this lab, both you and your teammate should submit these pictures to eClass as img_{01,02,03,04,05,06}.jpg files,
where img_x is the picture for exercise x below. Make sure the size of each image is less than 500KB, e.g. by
reducing the resolution of your camera.
IMPORTANT: You are required to provide preconditions and postconditions for each solution you provide.
Ex 1) Trace the following flowchart for when input is 15 and complete the trace table. Also, write pre- postconditions for this flowchart.
Ex 2) Trace the following flowchart for when input values are 12, 3, 5, -2, 11, 15, 1, 1, and complete the trace
table. Also, write pre- post-conditions for this flowchart.
Ex 3) Trace the following flowchart for when input values are -10, 1, 3, 2, -11, -13, -1, 1, -3, 2, 0 and complete
the trace table. Also, write pre- post-conditions for this flowchart.
Ex 4) Trace the following flowchart for when input values are 12, -2, -3, 6, -11, 3, 1, -1 and complete the trace
table. Also, write pre- post-conditions for this flowchart.
Ex 5) This exercise uses sub-algorithms. Trace it for when input value is 6 and complete the trace tables. Also
note that there are two variables name num, one in the main algorithm and another in the sub-algorithm.
Write pre- post-conditions for each of these algorithms (the main one and the sub-algorithm).
Ex 6) Devise an algorithm to receive a positive number, n, and output all prime numbers that are smaller than n
and have a digit 7. For example, if n is 100, the program should output 7, 17, 37, 47, 67, 71, 73, 79, and 97.
Your solution should have a main algorithm and two sub-algorithms, let’s call them prime(num) and
has7(num). You may reuse the prime sub-algorithm of Ex 5. You do not need to verify (e.g. by tracing) it
though because you did it in Ex 5. You need to trace your has7 algorithm. You should provide pre- and
post-conditions for all your 3 (sub)algorithms.
Show all your trace tables as well as pre- post- conditions and your solution of Exercise 6 to your TA before
starting Part 2. The TAs may ask any of the teammates some questions to verify your level of knowledge and skills
on each exercise, they may also ask you to verify the flowcharts for different sample inputs. They will provide you
a grade accordingly.
Part 2: Create a lab06<yourname>.html file supported by a lab06<yourname>.css and a
lab06<yourname>.js files. In your html file, you should have 6 buttons with captions Problem 1, Problem 2, …,
Problem 6. Then, you implement all 6 flowcharts in your lab06<yourname>.js . When each button is clicked, the
event handler should execute the corresponding algorithm that you have in your js file.
G. AFTER-LAB WORKS (THIS PART WILL NOT BE GRADED)
In order to review what you have learned in this lab as well as expanding your skills further, we recommend the
following questions and extra practices:
1) Revisit other flowcharts you have drawn/seen in the course and trace them for some sample inputs.
2) Devise an algorithm to receive a positive number, n, and output all prime numbers that are smaller than n
and all their digits are prime too. For example, if n is 100, the program should output 2, 3, 5, 7, 23, 37, 53,
and 73.
3) Add all algorithms and programs that you have drawn throughout the semester in your Learning Kit Project.
You would need to show that to your TA at the beginning of Lab 07 next week. Your Learning Kit project
should include at least 30 problems by then.
Please feel free to discuss any of these questions in the course forum or see the TAs and/or Instructors for help.