CSc 227 Class Announcements

CSc 227
PROGRAM DESIGN AND DEVELOPMENT
Spring Semester 2007

CLASS ANNOUNCEMENTS

2007/05/10 12:20pm: Final grades are posted (in the usual place)!
2007/04/26 3:10pm: Details regarding the Final Exam:
- Date: Wednesday, May 9th.
- Time: 11:00 a.m. - 1:00 p.m.
- Location: Chavez 110 (our usual classroom)
- Coverage: Everything, starting with the Java material and concluding with sorting. See the topic outline table in the syllabus for lists of concepts in each lecture topic and the corresponding sections in the text. You can expect a bit more emphasis on the recent material over which you haven't yet been tested.
- Calculators: Not allowed!
Review session:
- Date: Monday, May 7th.
- Time: 7:00 p.m. - 9:00 p.m.
- Location: GS 906
- Moderators: Alex and Mark
2007/04/26 10:50am: The demand for IT (information technology) workers in the US is the highest in 6 years: The Myth of High-Tech Outsourcing (from BusinessWeek)
2007/04/24 4:25pm: I've updated the Topic 15 (BST) examples. If you made copies of those examples earlier, I encourage you to make new copies.
2007/04/18 11:35pm: Additional details on Program #10 (Binary Searching a Binary File):
- You may be wondering how to use a binary search to find all of the file records with names that match the user's search string. The solution: Have a more intelligent base case on your recursion. When you find the first match, move toward the front of the file until you hit the initial matching record, then move forward again to read and display all of the matches. If you like, you can put all of these actions in a separate method, to avoid cluttering up the recursive search method; think of it as a helper method for the recursion. (Food for thought: Can you adjust the logic of the standard binary search to find the initial matching record? And if you can, is it worth the trouble?)
2007/04/05 5:00pm: Details about Exam #3:
- Review:
- Exam:
2007/04/04 9:50am: Additional details on Program #9 (Recursion):
- You needn't worry about putting pre-condition tests into your recursive methods. Recall that when we talked about assert(), we said that a common alternative is to have good documentation with your method. If the programmer chooses to ignore your documentation and its info about suitable input/parameter values, well, that's their problem.
2007/04/03 2:35pm: I renumbered some of the recursion (Topic 12) examples because I added a linked list example as T12n03.java.
2007/03/31 8:15pm: Program #9 (Recursion) is posted, for those of you interested in getting an early start.
2007/03/29 12:40pm: Additional details on Program #8 (Bemazed):
- For the graphics representation of the maze, you're free to choose any reasonable dimensions for the maze features. The demo I showed in class had walls every 10 pixels, which is certainly fine. If you want to get a bit more creative, you can query the size of the graphics window from within your program (see the Java Task Force tutorial) and compute wall distances that allow your maze, whatever the size, to fit within those dimensions. That's not necessary, of course. A fixed size of 10 or so is fine.
- There seems to be some confusion about the Stack implementation. You do not need to implement a full Linked List class; you only need to implement push(), pop(), etc., using a linked list representation, as we discussed in class on Wednesday.
- A follow-up to the questions at the start of class today (4/2) about the r x c vs. the 2r+1 x 2c+1 views of the maze: For those of you wondering where this division of labor is specified in the handout, see the first paragraph in the Assignment section, as well as the third bullet in the Hints... section.
- Don't overlook your text as a source of info on linked-list representation for stacks. Pages 275 and 276 in particular may be helpful.
2007/03/29 12:05pm: The server that makes your H: drive available to you in the lab will be down for service 7-8am on Tuesday April 3rd. I wouldn't expect an outage at that time to influence many of you, but it's still worth noting.
2007/03/20 12:40pm: The score sheet has been updated.
2007/03/05 2:20pm: As announced in class today, I'll be out of town Wednesday and Friday. My office hours for Wednesday through Friday are cancelled. Alex will cover the lecture on Wednesday, and of course we've got the exam on Friday.
2007/02/28 3:00pm: Details about Exam #2:
- Review:
- Exam:
2007/02/28 11:15am: I've had some inquiries from students about switching to audit status in the class. That makes this a good time to post my rules for auditing:
1. You may switch from credit to audit if you wish to do so. You'll need to get a Change of Schedule form, fill it out, and bring it to me for my signature before the end of the business day on Tuesday.
2. Completing the class as an auditor is NOT the same as completing the class with a passing grade. If you plan on continuing in CS, you'd still need to complete 227 (or the 127A and B sequence) with grades of 'B' or better.
3. Audited class do not count toward your GPA, nor toward credits needed for full-time enrollment status, financial aid, etc. Be sure to check with your academic advisor before you switch to audit status in any of your classes.
4. You do get a 'grade' for your audit: Either "O" for a successful completion of the audit or "XO" otherwise.
5. Standards for the "O" vary by instructor. For this class, all that I require is that you keep attending lecture and section regularly. If you aren't planning to keep up with the lectures and sections, you should drop the class.
6. You're welcome to complete assignments if you have time to do so. It's up to your section leader to decide if he will be willing to grade them. Your CS account will remain active through the rest of the semester. Please don't spend time on these assignments at the expense of your remaining for-credit classes!
7. Please don't take exams. As with the time you'd spend on assignments, you're probably better off using the time you'd spend on exams to concentrate on doing well in your other classes.
2007/02/28 11:05am: Clarifications on Program #6:
- None so far!
2007/02/22 12:10pm: If you feel bedeviled by Java errors, you might find this to be of some help: Compile and Runtime Errors in Java. This document was just made generally available yesterday. At this point, you've probably encountered most of these already and understand what causes them. Some things are likely to be new, though.
2007/02/19 11:20am: Early warning: Exam #2 will be Friday, March 9th, the Friday before spring break. Schedule your travel plans accordingly!
2007/02/19 11:20am: Clarifications on Program #5:
- The sample data files are now in both locations, the Source folder and class web page.
- Students are starting to ask if they can use a certain file method to get one of the three totals you need to report for a file. The answer is yes, you may. However, we encourage you to try to get that value without using that shortcut method. Pretend that you did not have access to that short-cut. How else could you do it?
- We've also received one or two inquiries of this sort: "If we can't use Scanner, what else is there?" Take a look at the example file programs on the class web page that accompanied my in-class presentations on Java's file classes. One in particular should be very useful. If they don't look familiar ... you either missed a class or two, or need to pay better attention during class!
2007/02/15 3:50pm: The biggest point of contention on the first exam may be Question 5, on the 4-bit integer representations. There are three issues: The appropriateness of the question, the explanation given in the review session, and what (if anything) I'm going to do about it. I'll address each in turn.
Appropriateness: Based on what I presented in class, and the numeric overflow example I ran and discussed, I think the question was fair. The two negative values were selected to check if you got the "roll the odometer backwards" idea, and if you could figure out which value you'd get from a numeric overflow. You don't need to know what two's complement is to understand it at the "odometer" level of detail, and that plus knowledge of how to count in binary is all you needed for that question.
Explanation during Review: I've heard conflicting stories, meaning that I can't say whether or not the explanation was correct. There's not a lot more I can say about that, other than to remind the SLs to come prepared when leading a review session. As students, you should stay alert for examples, explanations, etc., that don't seem to make sense. This applies to lectures as well. I'm human; I make mistakes, too.
What I'm Going to Do: Situations such as this one are the reason for the "It's possible that final grade cutoffs will be lowered a little" phrase in the syllabus (see the "Grades and Grading" section). I keep track of exam questions that go awry, exams that are too long, etc., and use that to help me decide if the grade cut-offs need to be adjusted. I don't "curve" exams.
2007/02/13 11:55am: Speaking of sleep and knowledge retention, I noticed this story about the value of sleeping well before as well as after studying.
2007/02/12 6:20pm: Two updates: First, I added a new section to the topic outline on the syllabus, for Text and Binary file I/O. Second, example file I/O programs are now linked to the class web page under the new Topic 3.
2007/02/12 2:35pm: The password-protection is set; you can now access the complete PDF of the Dewdney SciAm article.
2007/02/12 2:35pm: To learn your CSID, visit the Request CSID page.
2007/02/10 3:05pm: The first score sheet has been posted. The SLs will return the exams in section this coming week, and will review them as well.
2007/02/07 11:30am: Here's the list of methods that you need to know how to use when you take Exam #1. If we ask you to write code using any of these, we'll expect that you will already know how they work. If we specifically require you to write code using any other methods, we'll tell you how those methods work.
- From Math: ceil(double), floor(double), sqrt(double)
- From Scanner: nextInt(), nextLine()
- From Character: isDigit(char), toLowerCase(char), toUpperCase(char)
- From Integer: intValue(), parseInt(String)
- From String: charAt(int), compareTo(String), length(), substring(int,int)
- From StringBuilder: append(String), charAt(int), delete(int,int), insert(int,String), length(), replace(int,int,String)
Note that constructors aren't listed here; we're assuming that you'll know how to construct any of these that are instantiable.
2007/02/06 9:40am: Due to the network outage last night, we'll accept as "on time" programs submitted before 10:00pm tonight (Tuesday, Feb 6th).
2007/02/04 12:00pm: Details on Exam #1:
- Review:
- Exam:
2007/02/02 9:50am: I just added a link to the class page with an example exam question and what we look for in student answers to it. Give it a look; it could help you as you prepare for next week's test.
2007/01/31 12:10pm: To answer today's question about mixing variable types when declaring arrays, this:
```
     int[] a, b;
```
declares two array reference variables, while this:
```
     int c[], d;
```
makes c an array reference variable and d just a plain old int. I still recommend not mixing arrays and normal variables in the same group of declarations, to avoid the potential for confusion. That is, do something along the lines of this set of declarations:
```
     int[] e,  // a great comment about this integer array
           f;  // another great one about this other integer array
     int   g,  // a plain old integer
           h;  // yet another plain old integer
```

2007/01/30 12:10pm: Exam #1 will be on Friday, February 9th, and will cover everything through Exceptions. Review session is tentatively scheduled for Wednesday Feb 7th from 7-9pm in GS 906.

2007/01/30 12:05pm: Clarifications on Program #3:
- I've tweaked the sample tester to correct the number of syllables in 'caves.'
- A few students have asked if they can use regular expressions to help look for patterns in the words. Regular expressions, and Java's classes that use them, aren't part of this class. My preference is that you not use them, but I'm not saying 'no.'
- Due to the network outage Monday night / Tuesday morning, we'll accept as "on time" programs submitted before 10:00pm Tuesday, Feb 6th.

2007/01/20 2:50pm: Clarifications on Program #2:
1. If the user enters "1" as the starting value for a hailstone sequence, you may either stop there, or you may generate the sequence "1 4 2 1". Either is acceptable.
2. As noted by at least two students, implementing Babwani's Congruence in Java can produce negative values for w. This is due to how Java (and a lot of other languages) handle mods of negative values. Fortunately, a simple adjustment is all that is required: If w is negative, add 7. (The Wikipedia page on modulo has more than you'd ever want to know on the subject, if you're curious.) I've added a correction to the on-line version of the assignment handout.

2007/01/19 12:10pm: Two things:
- I've had to move my Thursday office hour. It's now from 1-2pm.
- For anyone a little shaken by my lecturing pace today: That pace will not be maintained, you'll be happy to hear. We'll slow down a bit next week as we hit the OO concepts. It's a fast-paced class, but today was the exception, not the rule.
2007/01/16 11:40am: Our lab staff has adjusted the secure URL for the electronic turnin system. You may now use the "https" version just as easily as you can use the "http" version. I recommend that you use the "https" version for the extra password security. The complete URL is: https://lectura.cs.arizona.edu/turnin
2007/01/16 11:30am: In the quadratic formula program in Program #1, I erred by telling you that the two "static" lines are defining constants. They're being used as if they are constant, but to be truly constant, we'd have to add the keywork "final" in front of each. The program works either way, so don't worry about changing it for this assignment.
2007/01/16 11:25am: Due to the first assignment being due on Friday morning instead of Monday night, some of the 227 SLs will be picking up some lab hours on Wednesday night this week only.
2007/01/12 4:15pm: I see that the lab hour schedule is now updated for this semester.
2007/01/11 10:00pm: Our head section leader, Alex, has written two walk-throughs that ought to help those of you who are interested in installing Java 1.5 and TextPad on a home PC. Thanks, Alex!
2007/01/10 12:15pm: In section this week you received (or will receive) a handout with lab rules. If you lose your copy, you can find it online here.
2007/01/02 5:00pm: The University Learning Center offers a nice one-page calendar for the semester. This semester's can be found from Semester on a Page. It has important dates and deadlines for the university as a whole, plus it's got room for you to make notes for each day.
2007/01/02 5:00pm: Class Announcements page created.

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