Software Engineering Assignment 1 Solution

Programming environment




For this assignment you must ensure your work executes correctly on the Linux machines in ELW B215. You are welcome to work on your own laptops and desktops; if you do this, give yourself a few days before the due date to iron out any bugs in your code when it executes on a UVic computer. You can use “git push” and “git pull” to move files back and forth between SENG filesystem and your computer. (Bugs in the kind of programming done this term tend to be platform specific. Something that works perfectly on your own machine may end up crashing on a machine in ELW B215, and the fault is very rarely that of the lab machine.)










Individual work




This assignment is to be completed by each individual student (i.e., no group work).




Naturally you will want to discuss aspects of the problem with fellow students, and such discussion is encouraged. However, sharing of code fragments is strictly forbidden without the express written permission of the course instructor (Zastre). If you are still unsure regarding what is permitted or have other questions




about what constitutes appropriate collaboration, please contact me as soon as possible. (Code-­‐similarity analysis tools will be used to examine submitted work.)










Objectives of this assignment




Understand a problem description, along with the role played by sample input and output for providing such a description.



Use the C programming language to write the first implementation of a SENG 265 text formatter named “format265” (and do this without using dynamic memory).



Use Git to manage changes in your source code and annotate the evolution of your solution with “messages” provided during commits.



Test your code against the ten provided test cases.














This assignment: “format265.c”




You are to write a C program that inputs lines of text files, reads formatting options contained within those text files, and then outputs the text where each line has the appropriate width, indenting, etc. as indicated by the formatting options. For example, here is one such file contained on the SENG file system at /home/zastre/seng265/assign1/tests/in04.txt:







.LW 30



Properly formatting




a




file where
there

is
a smattering of white space throughout really means eliminating that

extra

white

space

such that the result

looks neat

and

very

tidy.




This particular file contains one formatting option (“.LW 30”) which indicates that the following text must be formatted such that each line contains at most 30 characters. The formatting program also concatenates the lines of a paragraph in order to eliminate unnecessary white space. The resulting output (in /home/zastre/seng265/assign1/tests/out04.txt) looks like this:







Properly formatting a file




where there is a smattering of

white space throughout really

means eliminating that extra

white space such that the

result looks neat and very




tidy.




With your completed “format265” program, the input would be transformed into the output via the following command:







% ./format265 /home/zastre/seng265/assign1/tests/in04.txt ./out04.txt




where the file “out04.txt” would be placed in your current directory. To compare the output produced by format265 with what is expected, you can use the Unix “diff” command as shown below (assuming you’re still in the same directory as when you executed the command above):







% diff /home/zastre/seng265/assign1/tests/out04.txt ./out04.txt




Note that “diff” is much (much!) more reliable than using only your eyes.







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For this first assignment there are only four formatting commands:




.LW width: Each line following the command will be formatted such that there is never more than width characters in each line. The original whitespace in the input text need not necessarily be preserved (i.e., single spaces are used to separate words in the output). If this command does not appear in the input file, then the input text is not transformed in the output.



.LM left: Each line following the command will be indented left spaces from



the left-­‐hand margin. Note that this indentation must be included in the page width. If this command does not appear in the input file, then the value of left is 0 (zero).




.FT [off | on]: This is used to turn formatting on and off. If the command appears with “off”, then all text below the command up to the next “.FT” command is output without being formatted. If the command appears with “on”, then all text below the command up to the next “.FT” command is output with as many words as will fill the given page width.



.LS linespacing: If linespacing is not zero (0), then between each text line there will appear linespacing blank lines. A blank line in the input file is



considered to be the same as a text line. If there is no .LS command in the input file, then linespacing is zero.




There is some default behavior expected. (Some details from the previous bullet points are repeated below.)




If no “.LW” command appears, the default mode is “.FT off”. In this case all “.LM” commands are ignored. If no “.LS” command appears, then there is no linespacing (i.e., linespacing is zero).



If a “.LW” command appears, the default mode is “.FT on”.



For this first assignment, there will only ever be one “.LW”, “.LM” and “.LS” command in an input file, and these will appear at the top of the file.



For this first assignment, you can assume that all test files will have page widths that are much greater than left margins (e.g., there will never be a combination such as “.LW 30” and “.LM 40”). Also linespacing specified in test files will never be greater than 2.



There is no limit to the number of “.FT” commands that can appear within an input file.



No matter the line spacing, if no blank line exists at the end of the input file, then there must not be a blank line at the end of the output. In all other cases input blank lines are treated as regular lines with respect to line spacing.
The name of the input file is specified as an argument to format265. There is no output file specified (i.e., output is to stdout). You must not hardcode filenames in your submitted code!
Exercises for this assignment




Within your local Git repository create a top-­‐level directory named “assign1”. (For example, if your Netlink ID is “userbob”, then your local git repo is named “userbob”, and you must to create a directory “userbob/assign1”.



Write your program the “assign1” directory described in step 1. Amongst other tasks you will need to:



read text input from a file, line by line



write output to the terminal



extract substrings from lines produced when reading a file



create and use arrays in a non-­‐trivial array.



use the “-­‐ansi” flag when compiling to ensure your code is ANSI compliant.



Do not use “malloc”, “calloc” or any of the dynamic memory functions. For this assignment you can assume that the longest input line will have 132 characters, and no input file will have more than 500 lines.



Keep all of your code in one file for this assignment. In later assignments we will use the separable compilation features of C.



Use the test files to guide your implementation effort. Start with simple cases (such as those given in this writeup). In general, lower-­‐numbered tests are simpler than higher-­‐numbered tests. Refrain from writing the program all at once, and budget time to anticipate for when “things go wrong”.



For this assignment you can assume all test inputs will be well-­‐formed (i.e., the teaching team will not test your submission for handling of errors in the input). Later assignments will specify error-­‐handling as part of the assignment.



Use git add and git commit appropriately. While you are not required to use git push during the development of your program, you must use git push in order to submit your assignment.









What you must submit




A single C source file named “format265.c” within your git repository containing a solution to Assignment #1. Ensure your work is committed to your local repository and pushed to the remote before the due date/time. (You may keep extra files used during development within the repository.)



No dynamic memory-­‐allocation routines are permitted for Assignment #1 (i.e., do not use anything in the “malloc” family of functions).


Evaluation




Students will demonstrate their work to a member of the course’s teaching team. Sign-­‐up sheets for demos will be provided a few days before the due-­‐date; each demo will require around 10 minutes.




Our grading scheme is relatively simple.




“A” grade: An exceptional submission demonstrating creativity and initiative. “format265” runs without any problems. All ten tests pass. The program is clearly written and uses functions appropriately (i.e., is well structured).



“B” grade: A submission completing the requirements of the assignment. “format265” runs without any problems; all ten tests pass. The program is clearly written.



“C” grade: A submission completing most of the requirements of the assignment. “format265” runs with some problems; some tests do not pass.



“D” grade: A serious attempt at completing requirements for the assignment. “format265” runs with quite a few problems; most tests do not pass.



“F” grade: Either no submission given, or submission represents very little work.















































































































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