Description
QUESTION
Write a C program called: ./database CMD OPT1 OPT2 OPT3 OPT4
Where:
• CMD is a command that performs a specific operation.
• OPTi are optional arguments depending on CMD.
The source file is called: database.c
The executable file is called: database
The CSV file is called: database.csv
The argument CMD can have the following values:
• SHOW – displays all the records from the database.
• DELETE – OPT1 = ID, that record in removed from the database.
• ADD – OPT1=ID, OPT2=NAME, OPT3=AGE, OPT4=GPA, a
new record with these fields are added to the database.
The structure of the CSV file is: ID,NAME,AGE,GPA
Spaces can exist between the commas, but are not required. In other words, your program
should handle both cases. If a space comes after or before a comma, then it is not
considered to be part of the field.
For example, database.csv could look like this:
10,bob,18,3.5
15,mary,20,4.0
5,tom, 17 , 3.8
Notice the record “tom” has spaces before and after some of the commas. These spaces
are not part of the fields. In other words we read: “5” then “tom” then “17” then
“3.8”, without spaces in the field characters.
Create database.csv and database.c in the same directory. Using vim, initialize
database.csv with the above three records (i.e. bob, mary, tom), with the same
spacing and format.
Make database.c do the following:
1. If the user does not provide any command line arguments, then terminate with an
error message: “Your did not provide any arguments. Please enter: ./database
CMD OPT1 OPT2 OPT3 OPT4”.
McGill Mini Assignment #5 COMP 206
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2. If the CMD argument is not SHOW, not DELETE, not ADD, then terminate the
program with the error message: “The command you requested in invalid. Please
select from one of these: SHOW, DELETE, ADD”.
3. The user must input the CMD argument in all caps. BONUS: (optional – no extra
points) automatically convert the user’s CMD to uppercase.
4. If CMD is SHOW, then display all the records like this, without the quotes:
“Record 1: ID=nnn NAME=nnn AGE=nnn GPA=nnn”
Where nnn is the data from the CSV file. The record number increases for each
record displayed. All the records are displayed. Use the %s, %d, and %f correctly
so that the output is displayed in columns (all the ID fields are under each other,
all the NAME fields are under each other, etc.). Each record in displayed on a
new line. After the records are displayed the program terminates.
5. If CMD is DELETE, then there must be an OPT1 argument.
a. If this is missing, then the program terminates with the error message:
“Name of record to delete is missing”.
b. If there are more arguments than OPT1, then they are ignored. This is
called graceful execution. We assume the first argument is the correct
OPT1 and ignore all the other arguments.
c. Delete the first record that matches ID==OPT1. The database.csv
file is updated, and the program terminates. You will need to use a
temporary file: database.tmp to copy the records you do not want to
delete. Then use the system() command to delete the old
database.csv file and rename the database.tmp file into the new
database.csv file. If no record matched the search condition then
display the following message and terminate: “Sorry, that user was not
found. Nothing was deleted.”
6. If CMD is ADD, then there must be OPT1, OPT2, OPT3, and OPT4 arguments.
a. If less that four OPT arguments are present, terminate the program will the
following error message: “Missing ID, Name, AGE, and GPA arguments”.
b. If there are more arguments, then implement graceful execution.
c. It does not matter whether another record with the same name or ID
already exists. Simply append (using fopen(filename,”at”)) the
new record to the end of the database.csv file.
IMPORTANT
You must use mimi.cs.mcgill.ca to create the solutions to this assignment. You cannot
use your Mac command-line, Windows command-line, nor a Linux distro installed
locally on your laptop. You can ssh or putty from your laptop to mimi, or you can go
to the third floor of Trottier and use any of those labs, to complete this assignment.
McGill Mini Assignment #5 COMP 206
Vybihal School of Computer Science Page 3 of 4
WHAT TO HAND IN
Everything must be submitted to My Courses before the due date. Remember that you
can hand in your assignment up to two days late but there will be a penalty of 5% each
day. After that, your assignment will not be accepted. Please hand in the following:
• The database.c file
• The database.csv file
• A bash compile.sh script that compiles the programs for the TA using gcc.
• Do not hand in the executable
• Zip all these files so that myCourses will receive them correctly.
• Make sure to add comments to your C program.
• Add your name and student ID number as a comment.
HOW IT WILL BE GRADED
THE TESTING SCRIPT
The TA will run a testing script when evaluating your assignment. This test script is
included in the assignment. You can use this testing script to verify that your program
runs correctly. The script file is called mini5tester.sh.
POINTS AWARDED
The assignment is worth a total of 20 points.
o Question
• 2 points – correctly formatted CSV file
• 2 points – proper command line parameter testing
• 3 points – basic SHOW command works
• 4 points – basic DELETE command works
• 3 points – basic ADD command works
• 2 points – Proper use of system() for rm (delete) and cp (rename) for DELETE
• 1 point – Proper use of fopen() with append (“at”) for ADD
• 1 point – Proper use of graceful execution (two times) for DELETE & ADD
• 2 points – Pretty output with SHOW
McGill Mini Assignment #5 COMP 206
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GRADING RULES
The following rules are followed by the TA when grading assignments:
• A program must run in order to get a grade (even if it does not run well). If it
does not run (does not compile) it will receive a zero. (Make sure to run your
programs from mimi.cs.mcgill.ca).
• The TA will grade using the mimi.cs.mcgill.ca server.
• All questions are graded proportionally. This means that if 40% of the question is
correct, you will receive 40% of the grade.
