Software Engineering-1 (CS504)
Assignment # 5 (Fall 2011)
Total marks = 20
Deadline Date = 23-01-2012
Assignment comprises of 20 Marks. Note that no assignment will be accepted after due date via email in any case (whether it is the case of load shedding or emergency electric failure or internet malfunctioning etc.). Hence, refrain from uploading assignment in the last hour of the deadline, and try to upload Solutions at least 02 days before the deadline to avoid inconvenience later on.
For any query please contact: CS504@vu.edu.pk
An un-maintainable code is one of the candidates that negatively affect overall software maintainability and hence adding to maintenance cost and time.
Search the internet for the term “un-maintainable code” and write down one page article on the following topic:
“Guidelines to avoid un-maintainable code”
1) Article should be formatted precisely without any grammatical mistake.
2) In case if you need to quote any stuff from other source, then provide proper reference of this source.
In the interests of creating employment opportunities in the programming field, I am passing on these tips from the masters on how to write code that is so difficult to maintain that the people who come after you will take years to make even the simplest changes. Further, if you follow all these rules religiously, you will guarantee yourself a lifetime of employment, since no one but you can hope to maintain the code.
Lie in the comments. You don’t have to actively lie, just fail to keep comments up to date with the code.
Pepper the code with comments like /* add 1 to i */; however, never document woolly stuff like the overall purpose of the package or method.
Make sure that every method does a little bit more (or less) than its name suggests. As a simple example, a method named isValid(x) should, as a side effect, convert x to binary and store the result in a database.
Use acronyms to keep the code terse. Real men never define acronyms; they understand them genetically.
In the interests of efficiency, avoid encapsulation. Callers of a method need all of the external clues they can get to remind them of how the method works inside.
If, for example, you were writing an airline reservation system, make sure that there are at least 25 places in the code that need to be modified if you add another airline. Never document where they are. People who come after you have no business modifying your code without thoroughly understanding every line of it.
In the name of efficiency, use cut/paste/clone. This works much faster than using many small reusable modules.
Never, never put a comment on a variable. Facts about how the variable is used, its bounds, its legal values, its implied/displayed number of decimal points, its units of measure, its display format, its data entry rules (e.g., total fill, must enter), when its value can be trusted etc. should be gleaned from the code. If your boss forces you to write comments, lard method bodies with them, but never comment a variable, not even a temporary!
Try to pack as much as possible into a single line. This saves the overhead of temporary variables and makes source files shorter by eliminating new line characters and white space. Tip: Remove all white space around operators. Good programmers can often hit the 255-character line length limit imposed by some editors. The bonus of long lines is that programmers who cannot read 6 point type must scroll to view them.
Cd wrttn wtht vwls s mch trsr. When using abbreviations inside variable or method names, break the boredom with several variants for the same word and even spell it out longhand once in a while. This helps defeat those lazy bums who use text search to understand only some aspect of your program. Consider variant spellings as a variant on the ploy; e.g., mixing international colour, with American color and dude-speak kulerz.
Never use an automated source code tidier to keep your code aligned. Lobby to have them banned from your company on the grounds that they create false deltas in PVCS (version control tracking). You are now free to accidentally misalign the code to give the optical illusion bodies of loops and ifs are longer or shorter than they really are.
Rigidly follow the guidelines about no goto, no early returns and no labeled breaks especially when you can increase the if/else nesting depth by at least five levels.
Use very long variable names that differ from each other by only one character, or only in upper/lower case. Wherever scope rules permit, reuse existing unrelated variable names. An ideal variable name pair is swimmer and swimner. Exploit the failure of most fonts to clearly discriminate between ilI1| or oO08 with identifier pairs like parselnt and parseInt or D0Calc and DOCalc.
Never use i for the innermost loop variable. Use anything but. Use i liberally for any other purpose, especially for non-int variables.
Never use local variables. Whenever you feel the temptation to use one, make it into an instance or static variable instead to unselfishly share it with all the other methods of the class. This will save you work later when other methods need similar declarations. C++ programmers can go a step further by making all variables global.
Never document gotchas in the code. If you suspect there may be a bug in a class, keep it to yourself. If you have ideas about how the code should be reorganized or rewritten, for heaven’s sake, do not write them down. Remember the words of Thumper: “If you can’t say anything nice, don’t say anything at all.” What if the programmer who wrote that code saw your comments? What if the owner of the company saw them? What if a customer did? You could get yourself fired.
To break the boredom, use a thesaurus to look up as much alternate vocabulary as possible to refer to the same action; e.g. display, show, present. Vaguely hint that there is some subtle difference where none exists. However, if there are two similar functions that have a crucial difference, always use the same word in describing both functions (e.g. print to mean write to a file, and to print on a laser and to display on the screen). Under no circumstances should you succumb to demands to write a glossary with the special purpose project vocabulary unambiguously defined. Doing so would be an unprofessional breach of the structured design principle of information hiding.
In naming functions, make heavy use of abstract words like it, everything, data, handle, stuff, do, routine, perform and the digits; e.g., routineX48, PerformDataFunction, DoIt, HandleStuff and do_args_method.
Never document the units of measure of any variable, input, output or parameter; e.g., feet, meters, cartons. This is not so important in bean counting, but it is very important in engineering work. As a corollary, never document the units of measure of any conversion constants or how the values were derived. It is mild cheating, but very effective, to salt the code with some incorrect units of measure in the comments.
In engineering work there are two ways to code. One is to convert all inputs to S.I. (metric) units of measure, then do your calculations and then convert back to various civil units of measure for output. The other is to maintain the various mixed measure systems throughout. Always choose the second. It’s the American way!
I am going to let you in on a little-known coding secret. Exceptions are a pain. Properly-written code never fails, so exceptions are actually unnecessary. Don’t waste time on them. Subclassing exceptions is for incompetents who know their code will fail. You can greatly simplify your program by having only a single try/catch in the e n t i re application (in main) that calls System.exit(). Just stick a perfectly standard set of throws on every method header whether they could throw any exceptions or not.
C compilers transform myArray[i] into *(myArray+i), which is equivalent to *(i+myArray), which is equivalent to i[myArray}. Experts know how to put this to good use. Unfortunately, this technique can only be used in native classes.
If you have an array with 100 elements in it, hard code the literal 100 in as many places in the program as possible. Never use a static final named constant for the 100 or refer to it as myArray.length. To make changing this constant even more difficult, use the literal 50 instead of 100/2. These time-honored techniques are especially effective in a program with two unrelated arrays that accidentally happen to both have 100 elements.
Eschew any form of table-driven logic. It starts out innocently enough, but soon leads to end users proof reading and then, shudder, even modifying the tables for themselves.
Join a computer book of the month club. Select authors who appear to be too busy writing books to have had any time to actually write any code themselves. Browse the local bookstore for titles with lots of cloud diagrams in them and no coding examples. Skim these books to learn obscure pedantic words you can use to intimidate the whippersnappers that come after you. Your code should impress. If people can’t understand your vocabulary, they must assume that you are very intelligent and that your algorithms are very deep. Avoid any sort of homely analogies in your algorithm explanations.
I have saved the best for last. From a psychological warfare point of view, this is the most effective weapon for rattling maintenance programmers. On a method called makeSnafucated, insert only the comment /* make snafucated */. Never define what snafucated means anywhere. Only a fool does not already know, with complete certainty, what snafucated means.
Guideline to avoid un-maintainable code
We all have had experience of modifying the code that one has written, either to add a new feature or fix a problem in a module. The code which is hard to understand and modify by any other programmer is said to be un-maintainable code.
Consider the following example to understand the above statement
Hard to understand code?
nY = (nTotal-1)/nX + 1;
Is this code fragment hard for you to understand? If not, then you know the technique being used. If you do not know the technique, then it is sure frustrating to figure out. This code is one way to implement the ceil function on the nTotal/nX value. He views your code through a toilet paper tube. He can only see a tiny piece of your program at a time. You want to make sure he can never get at the big picture from doing that. You want to make it as hard as possible for him to find the code he is looking for. But even more important, you want to make it as awkward as possible for him to safely ignore anything. Programmers are lulled into complacency by conventions. By every once in a while, by subtly violating convention, you force him to read every line of your code with a magnifying glass. Properly commenting your code is a good first step. However, keep in the back of your mind that someone else is reading your code and avoid obscure programming techniques unless they are fully commented and documented in the project. Much of the skill in writing unmentionable code is the art of naming variables and methods. They don’t matter at all to the compiler. That gives you huge latitude to use them to befuddle the maintenance programmer.
Guideline to avoid un-maintainable code
1. Lie in the comments. You don’t have to actively lie, just fail to keep comments as up to date with the code.
2. Pepper the code with comments like /* add 1 to i */ however, never document wooly stuff like the overall purpose of the package or method.
3. Make sure that every method does a little bit more (or less) than its name suggests. As a simple example, a method named is Valid(x) should as a side a effect convert x to binary and store the result in a database.
4. Use acronyms to keep the code terse. Real men never define acronyms; they
understand them genetically.
5. In the interests of efficiency, avoid encapsulation. Callers of a method need all the external clues they can get to remind them how the method works inside.
6. If, for example, you were writing an airline reservation system, make sure there are at least 25 places in the code that need to be modified if you were to add another airline. Never document where they are. People who come
7. Never use i for the innermost loop variable. Use anything but. Use i liberally for any other purpose especially for non-int variables. Similarly use n as a loop index.