COMP 348 system with Clojure

COMP 348: ASSIGNMENT 3

Note that assignments must be submitted on time in order to received full

value. Appropriate late penalties (< 1 hour = 10%, < 24 hours = 25%) will be applied, as appropriate.

DESCRIPTION: It’s time to try a little functional programming. In this case,your job will be to develop a very simple information system with Clojure. REALLY simple. In fact,all it will really do is load data from a disk file. This data will then form a gradebook file (very

similar to what you see on Moodle). The gradebook contains one flat file that contains a list of allstudents in the class with their grades for every assignment/exam component.

grades.txt: <student id, first name, last name, [component, weight, grade]…>

The number of components may vary from file to file, however, it would be the same for all studentsin a single file....Note that no [syntax] error checking is required for any of the data files. You can assume that theyhave been created properly, and all fields are present.Each field is separated by a “,” and contains a

non-empty string.It is suggested that you use a vector for each student and include all grade components in a map.

The class list is then stored in a list.

See the mapify function in the attached code. Using that function, you may store the grades for each

student in a map. For example the grade for John Doe would be something like:

{"A1" {:weight 10, :grade 95.5},

"A2" {:weight 10, :grade 100},

"MIDTERM" {:weight 20, :grade 80},"FINAL" {:weight 60, :grade 70}}So now you have to do something with your data. You will provide the following menu toallow the

user to perform actions on the data:

Enter an option?A sample code template implementing the above menu structure is provided with this assignment.The options will work as follows

The List names option simply displays the list of students followed by a line indicating homany students are there in the file. Example:

Display Student record by Id, lets the use enter the student id and then displays the studentrecord as in the following. You may format the student record as you wish or simply dump

the record as illustrated in the following example:Enter the Student ID: 40543437Found:

[40543437 John Doe {A1 {:weight 10, :grade 95.5} A2 {:weight 10, :grade

100} MIDTERM {:weight 20, :grade 80} FINAL {:weight 60, :grade 70}}]

If the student id is non-existent, an error message will be displayed. Example:Enter the Student ID: 9999Invalid student ID or student ID not found.

Display Student record by last name, searches for the last name and displays the student

records for matched students. Example:Enter the Last Name: Doe

Found:[40543437 John Doe {A1 {:weight 10, :grade 95.5} A2 {:weight 10, :grade

100} MIDTERM {:weight 20, :grade 80} FINAL {:weight 60, :grade 70}}]

[440543476 Jane Doe {A1 {:weight 10, :grade 100} A2 {:weight 10, :grade

100} MIDTERM {:weight 20, :grade 90} FINAL {:weight 60, :grade 100}}]Total 2 record(s) found.

4. Using display component method, the user enters the component name and the system willdisplay the result and the class average (rounded to 1 digit) for that specific component.options displays the individual grades and the course total for eachstudent followed by the class average, as illustrated in the following example. The ‘schema’of the data is displayed on top, listed all course component in alphabetical order. Thestudent list is also sorted by student id in ascending order, Example

6. Finally, if the Exit option is entered the program will terminate with a “Good Bye” message.Otherwise, the menu will be displayed againSo that’s the basic idea. Here are some additional points to keep in mind:You do not want to load the data each time a request is made. So, before the menu isdisplayed the first time, your data should be loaded and stored in appropriate data

structures. So, assuming a loadData function in a module called db, an invocation like thefollowing would create and load a data structure called gradesDB

(def gradesDB (db/loadData "grades.txt"))

The gradesDB data structure can then be passed as input to any function that needs to acton the data. Note that, once it is loaded, the data is never updated.

You may alternatively use clojure’s read-csv function.

2. As a functional language, Clojure uses recursion. If possible, use the map, reduce and

filter functions whenever you can. (Note that you may sometimes have to write your

own recursive functions when something unique is required).3. This is a Clojure assignment, not a Java assignment. So Java should not be used for any main

functionality. That said, it might be necessary 代写COMP 348 system with Clojureto use Java classes to convert text to numbers

in order to do the calculations. An example with the map function is shown below:

(map #(Integer/parseInt %) ["6" "2" "3"])

4. It is worth noting, however, that this can also be done with Clojure’s read-string

function. This can be used to translate “numeric” strings, including floating point values. So

we could do something like:

(* 4 (read-string "4.5")) ; = 18

5. The I/O in this assignment is trivial. While it is possible to use complex I/O techniques, it is

not necessary to read the text files. Instead, you should just use slurp, a Clojure function

that will read a text file into a string, as in:

(slurp "myFile.txt")

6. For the input from the user, the read-line function can be used. If you print a prompt

string to the screen (e.g., “please enter the ciry”, you may want to use (flush) before

(read-line) so that the prompt is not cached (and therefore not displayed).

7. For string processing, you will want to use clojure.string. You can view the online

docs for a list of string functions and examples (https://clojuredocs.org/clojure.string)Do not worry about efficiency. There are ways to make this program (both the data

management and the menu) more efficient, but that is not our focus here. We just want you

to use basic functionality to try to get everything working.DELIVERABLES: Your submission will have just 3 source files. The “main” file will be called app.clj

and will be used to simply load the information in the text files into a group of data structures and

then pass this data to the function that will provide the initial functionality for the app. The secondfile, menu.clj will, as the name implies, provide the interface to the user. The third file will be

called db.clj and will contain all of the data management code (loading, organizing, etc.). Do not

include any data files with your submission, as the markers will provide their own.PROJECT ENVIRONMENT: It is easy to run a single Clojure file from the command line (i.e., clojure

myfile.clj). It becomes a little more tedious when the app is made up of multiple files. In

practice, large projects are typically built with a tool called Leinengen. Use of Leiningen, however, is

overkill for this kind of assignment and will likely make building and testing more problematic fo students.We will therefore keep things as simple as possible. Your files, both source code and data will belocated in the current folder. Each of the three source files listed above will define its ow. For example:(ns app:require [db])

(:require [menu]))IMPORTANT: This will allow the files/modules to interact with one another. However, Clojureaccesses modules relative to the current CLASSPATH. By default, the CLASSPATH will probably notbe set on your machine, so Clojure will fail to run your program, with errors saying that it cannotfind your modules. The simplest thing to do is to simply set the CLASSPATH to include the currentfolder (this is what the graders will do). From the Linux command line, you can just sayexport CLASSPATH=./

Once this is done, you can run your app simply by typingclojure app.cljNote that this CLASSPATH variable is temporary and would have to be reset each time you startLinux. If you want it to be automatically configured every time you log in, you could add the exportline to the .bashrc file in your login folder.SUBMISSION: Once you are ready to submit, place the .clj files into a zip file.The name of the zip file

will consist of "a3" + last name + first name + student ID + ".zip", using the underscore character "_"as the separator. For example, if your name is John Smith and your ID is "123456", then your zip filewould be combined into a file called a3_Smith_John_123456.zip". The final zip file will be submittedthrough thecourse web site on Moodle. You simply upload the file using the link on the assignmentweb pageFINAL NOTE: While you may talk to other students about the assignment, all code must be writtenindividually. Any sharing of assignment code will likely lead to an unpleasant outcome.

Good Luck