Description
I. Goal
In the first lab, we will develop a system program which provides mathematical commands
using C language. It must be an errorless system program, in which user starts the program,
enter commands, see the desired result, and finishes it if he or she wants to quit. For students
who has the first time to use C language, this project will be a good initiator to learn a new
programming language. Students who already know C language also will have a good
opportunity to warm up their programming abilities and get prepared for the rest of labs.
II. Introduction
A. Basic Calculations
The system program provides four basic mathematical commands shown in the below table.
Each command presents an operator, and requires operands as parameters. For instance,
when user enters sum 4 2, the program returns the result 6 (= 4 + 2) in the next line. And
then it will go to the next prompt waiting for user’s next command. Note that each operator
should have two operands, and if a command has more than 2 parameters, it is an incorrect
syntax. The commands are following:
Command Description
sum Summation of parameters. For instance, sum 4 2 calculates 4 + 2.
mul Multiplication of parameters. For instance, mul 4 2 calculates 4 x 2.
sub Subtraction of parameters. The first parameter is minuend, and all other
parameters are subtrahends. For instance, sub 4 2 calculates 4 – 2.
div Diving two numbers. It will allow only two parameters. The first
parameter is dividend and the second parameter is divisor. For instance,
div 4 2 calculates 4 ÷ 2 = 2
B. Collatz Conjecture
The system program provides an advance mathematical command, which is called Collatz
conjecture. The Collatz conjecture concerns what happens when we take any positive integer
n and apply the following algorithm:
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The conjecture states that when this algorithm is continually applied, all positive integers
will eventually reach 1. For example, if n = 19, the sequence is following:
19, 58, 29, 88, 44, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1
The command has one parameter. If it has more than two parameters, it is an incorrect syntax.
Command Description
col Finding collatz conjecture of parameter. For instance, col 19 returns a
collatz sequence.
C. Program Design
The system program should run on Linux machine at cs.oswego.edu. Once it is compiled
and performed, it draws user to its own computing environment by showing prompt following
the format below.
yourID> $
Then user will enter a command and parameters if necessary. The syntax of the command is
following.
command [parameter]*
Note that some commands such as basic calculations need multiple parameters. When each
command finishes its own calculation, it will show the results on the screen as shown in the
Figure 1, and the new prompt follows for the next command.
[jwlee@deepwater:~]$ cc lab1_jwlee.c –o lab1
[jwlee@deepwater:~]$ ./lab1
jwlee> $ sum 3 2
5
jwlee> $ mul 5 7
35
jwlee> $ sub 6 7
-1
jwlee> $ div 4 2
2
jwlee> $ col 19
19, 58, 29, 88, 44, 22, 11, 34, 17, 52, 26, 13, 40, 20, 10, 5, 16, 8, 4, 2, 1
jwlee> $ col 35
35, 106, 53, 160, 80, 40, 20, 10, 5, 16, 8, 4, 2, 1
jwlee> $ bye
bye
[jwlee@deepwater:~]$
Figure 1. Example of project 1
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To quit the program, user should enter command bye without any parameters. Then the
program ends after a simple message bye, which notifies the end of the program. It has no
parameter, and if it has any parameter, it is an incorrect syntax.
Command Description
bye Finishing the program.
D. Extra work
Each basic mathematical command in the original program can calculate only two operands,
for instance, sum 3 5 will return 8 (=3 + 5). In the real world, however you may be asked to
calculate more complicated formula such as is 5 + (7 * (4 – 2)). Thus, you will enhance these
commands so that they can work for more complicated calculation as an extra work. The
example formula has three operators, four operands, and two pairs of parentheses. For
calculating the example, you will enter the following command:
sum 5 (mul 7 (sub 4 2))
For simplicity, the system program will restrict the maximum number of operators, so there
are no more than 7 operators.
This is not mandatory but optional. Therefore, it will give you 6 extra points, which is worth
30% of the assigned points. Those who have experiences of C before are strongly encouraged
to do this extra work.
III. Requirements
A. Developing environment
The program should be implemented in C only. The program in another language will not be
graded. And the program should be executable in CS Linux machine. The program which
cannot be compiled or executed in the CS Linux machine will be considered as incomplete
program, and will lose most points.
B. Handling exceptions
The program must detect errors while running. The errors may occur when user violates the
syntax of the command or enters wrong inputs (character, more than 2 numbers, etc.). Also
any mathematically incorrect calculations, for instance, div 3 0, must be detected. When
the program detects any error cases, it should handle properly by giving some error
messages to the user, and still be runnable. The program, which fails to detect such
errors and to properly handle them, will be taken off penalty points.
C. Readability of source code
The source code should be easy to read with good indentation and proper amount of
comments.
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D. Creating a readme file
The program should be submitted along with a readme file which has information such as
student ID, name, etc. It also may provide instruction to run this program if exists. Those who
complete extra work need to describe their progress and implementation in one short
paragraph for instructor to grade the extra work.
The source file and readme file should be named following the format below. Those who are
not following the naming rule will also be taken off penalty points.
lab1_yourID#.c
lab1_yourID#_readme.txt
E. Submitting by due
The program should be submitted to Blackboard within the two weeks after the project is
posted. Due is September 21. All submission by 11:59 PM on that day will be accepted
without any penalty. On the due date, Blackboard may be suffering of too much network
traffics and be unstable. There is no excuse about the issue, therefore you are strongly
recommended to submit earlier than the due date.
IV. Grading
This project is assigned 20 points, which is 10% of the final grade. Groups who complete
extra work will receive 6 additional points.
A.Grading criteria
The project will be graded by evaluating the requirement. Any missing and unsatisfiable
criteria will take off points. The tentative and brief criteria are below.
• Compilation: 5 points (25%)
• Execution: 10 points (50%)
• Error detection & others: 5 points (25%)
B. Late penalty
Late submission will take off 10% per day per week after due date. Thus, submission
after 10 weeks will not be accepted in any circumstances.
V. Academic Integrity
Any dishonest behaviors will not be tolerated in this class. Any form of plagiarism and
cheating will be dealt with according to the guidelines on the Academic Integrity Policy online at http://www.oswego.edu/integrity. For more information about university policies,
see the following online catalog at:
http://catalog.oswego.edu/content.php?catoid=2&navoid=47#stat_inte_inte
Student who is against the honor code will not have any credits in this project.
