Problem Solving Assignment 5

Due Monday, February 12 at 11:59pm PST

There is one problem in this PSA.

Notes:

• This IS a pair assignment. You MUST do the assignment with your partner.

• You must complete an interview with a Lab Tutor for this PSA. Interviews are individual (partly to ensure that one partner doesn't do all the work). See instructions here for more details.

• This work should be done in its own directory called 'psa5'. Instructions here.

• This assignment has sample solution code that you can run on ieng6. You won't be able to see the java code itself =) but you will be able to do tests to see what it does, and make sure yours does the same thing. YOUR CODE MUST DO THE EXACT SAME THING. EXACT!! Wording, spaces, everything. Instructions on how to run the sample solution code are here .

• Each file must have a header with the team members' names, logins, and PIDs. The header should also describe the program in 2-3 sentences.

This homework requires skills from Chapter 1 through Chapter 3.

Problem

Write a program for calculating the grades of a class

Introduction:

• In a class student's grade are put in a plain text file. A row has the grades of a student and a column has the grades of a PSA, quiz, midterm or final exam. In this assignment you will implement a generic tool for calculating the grade of every student in a class given the data. Moreover, you are required to export the average grade of all quizzes, all PSAs, midterm and final exam.
• The number of PSAs and the number of quizzes differ from class to class so they are provided in the beginning of the file.
• Also, we suppose that all PSAs are equally grade-worth. This applies to quizzes also. All the grades are of the same range (e.g. 0-100).
• PSAs, quizzes, midterm and final exam count in different percentages in calculating the students grade. Since these percentages are different from class to class they are also provided in the beginning of the same grade file.
• The content of the text file will be read through the use of unix input redirection ("<"). E.g. java GradeCalc < grades.txt Instructions on how to use input/output redirection are here . You should create your code as if you are reading from the standard input (keyboard). This means that your code is the same as if the user were typing the input data, instead of reading actually from a file; thus you will still be using the Scanner class and its methods (nextInt(), nextLine(), etc).

Details:

• Your program must be in a file called GradeCalc.java
• The file format is as follows:
  The first line has the following numbers (positive integers):
  • The number of students
  • The number of quizzes the of the class
  • The number of PSAs
  • Percentage of quizzes in the student's total grade
  • Percentage of PSAs in the student's total grade
  • Percentage of midterm in the student's total grade
  • Percentage of final in the student's total grade
    E.g.: 10 5 3 10 20 25 45
    This class has 10 students, five quizzes, 3 PSAs, All the quizzes count as 10% of the total grade, PSAs 20%, the midterm 20% and the final exam 45%.
  The next lines are of the following format:
  • student code (like in gradesource)
  • quiz1, quiz2,... grades (white space separated)
  • PSA1, PSA2, ... grades (white space separated)
  • Midterm grade
  • Final exam grade
    E.g.: 2314 80 65 90.5 70 70 66.2 92 100 88 90
    This would be an example of a student of the above class.
• First, read the numbers in the first line. Then read the students' grades line by line. Be sure to hold the necessary data needed for your calculations.
• Output the total calculated grade for each student.
• Finally output the four requested average numbers (PSA, quiz, midterm and final exam)
• The input file will have all the data correct. There shouldn't be more students, PSAs, quizzes than stated in the first line. Also you are not required to check if the numbers are out of range or negatives.

Hints:

Details

Start by creating a directory (folder) in your ieng6 cs8fzz account (this is necessary for the bundle-psa4 script). After you log in, create a directory by typing the commands:

-bash-2.05b$ mkdir psa5

Go into that directory (like double clicking to open a folder) with the command:

-bash-2.05b$ cd psa5 

Note: you must name your directories (folders) and files as indicated in the problem descriptions for the turn in program to work.

In order to run the sample solution program you should invoke the following command:

-bash-2.05b$ runsample [classname]

So for this assignment, do:

-bash-2.05b$ runsample GradeCalc

This assignment is worth 10 points.

General (4 pts):
• 1 Point: For proper formatting. Your code is properly and consistently indented.
• 1 Point: For documentation. You must write a 2-4 sentence description of the program (as a comment) that provides insight into what the program does and what it's useful for. In this header comment, you are also required to put the author names, author PIDs and author logins
• 2 points: Interview (done individually) see instructions here.

GradeCalc.java (6 pts):

• 1 point: Correctly input the numbers of the first line of the file
• 1 points: Correctly input all the students grades
• 2 points: Correctly output each student's total grade
• 2 points: Correctly output the requested average numbers
• Everything must match the sample solution exactly.

How to turn in your homework electronically

When you are ready to turn in your homework, run bundle-psa4 from your psa4 directory. The session should look like this:

-bash-2.05b$ cd ~/psa5
-bash-2.05b$ bundle-psa5
Good; all required files are present:

        GradeCalc.java

Do you want to go ahead and turnin these files? [y/n]y
OK.  Proceeding.


Performing turnin of approx. XXXX bytes 
Copying to /home/linux/ieng6/cs8w/turnin.dest/cs8wzz.psa5
.
Done.
Total bytes written: XXXX 
Please check to be sure that's reasonable.
Turnin successful.

If you want to make changes after you've turned in your homework, make the changes and run bundle-psa5 again. The program will warn you that a "previously turned-in file exists" and ask if "you wish to over-write this existing file" (delete the old version and replace it with this new one). Respond in the affirmative by typing y and pressing the Enter key.

10% of your grade on this assignment will come from an interview you will have with one of the tutors during Open Lab Hours. You have 48 weekday hours after the electronic turnin deadline to get your interview done. The deadline for the interview for PSA 5 is Monday, Feb 19, theoretically at midnight, but actually by the end of the last tutor hour scheduled. You get an interview by going into B260 during a scheduled tutor hour. Find the tutor, ask them if you can interview for PSA 5. If they have others who are waiting for interviews, your name will go on the end of the list of people waiting. Interviews take about 5 minutes each. It is your responsibility to go in early enough that you can get your interview completed. If everyone waits until the last hour on Wed, this will not work. The tutor will ask you to log in, change to the directory where your work is (psa5) and then to follow their directions. They will ask you to run your program to show that it works, open files in your favorite editor, and ask you questions about how your code works. Additionally, they may question you as to how you would (theoretically) make small changes to the program to have it do something slightly different. Learning to be able to explain your problem solving process and discuss code with another human being is a very important professional skill. We hope that this process will help you develop this skill.

Copying the assignment directory to partner's home directory

You can copy the psa5 directory and its files to your partner's home directory by:

bash% scp -r psa5 cs8wxx@ieng6.ucsd.edu:

(don't forget the colon at the end of the command) where cs8wxx is your partner's username. You must be in the parent directory of the psa4 directory. So, you if you are currently in the psa4 directory you should execute "cd ..". Similarly, if the psa5 direcory is in your home directory then you have to be in your home directory. If you aren't there just execute "cd ~" and you'll be there. Your partner is required to enter his password when you enter the scp command. To check if the copy worked, your partner must login and ckeck if the psa5 directory exists in his home directory and if the proper files are located in it. This can be done by executing: "ls ~/psa5". The files in the psa4 directory should be listed.

Redirecting the input and the output

You can redirect the input af a program by using the "<" symbol in the command line. Instead of reading the input from the standar input device (which is the keyboard):

bash% java MyProgram < sampleEmail.txt

This command will redirect the input of the MyProgram program to the file sampleEmail.txt. It will read the contents of the file as if they were given by pressing the buttons on keyboard. Similarly you can redirect the output af a program by using the ">" symbol in the command line. Instead of displaying the output on the standar output device (which is the computer monitor):

bash% java MyProgram > outFile.txt

This command will redirect the output of the MyProgram program to the file sampleEmail.txt. It will write the output in the "outFile.txt" file (all contents of the will be erased if file exists, if it doesn't exist, it will be created) as if they would be printed on the computer screen (so, you won't get any output on the screen). You can combine both redirections. For example you may have an email.txt file with a sample email, and also you want the results of the scan to be put on the file output.txt. This can be done by:

bash% java MyProgram < email.txt > output.txt

Finding the differences between files

You can find the differences between two text files by using the diff command:

bash% diff filename1 filename2

The output will be the differences between the files. If there is no output at all that means that the files are identical.

Example: Testing the output of your program, can be completed in four steps, using the above tips.

Create a file with sample input (lets name it "input.txt" for your program (as if you would write it if the program was running)

Run your program and redirect the exit to a file: bash% java Statistics < input.txt > output1.txt

Run the provided program and redirect the exit to a second file: bash% runsample Statistics < input.txt > output2.txt

Check if there are differences between the two output files: bash% diff output1.txt output2.txt

Learning to use text editors

Vim

Run the command vimtutor, a separate program that will teach you to use Vim.

Emacs

Use the built-in tutorial by running emacs and, within the editor, typing CTRL-h t.

Pico

You can reach Pico's built-in help by typing CTRL-g. If you want further instruction, look at this Pico tutorial from NC State.