COSC 1020 - Section M

COSC 1020 – Section M – Winter 2004
Introduction to Computer Science I

Instructor: Scott MacKenzie, CSB3045; Office Hours: MW 13:30-14:30

Last update: 31-Mar-04

Mar 31: Here are the lecture notes from today’s class: misc.pdf, as well as the demo programs presented: DaysToSummer.java | DemoClock.java | DemoDateTime.java | RandomBits.java | RandomQuilt.java | GraphData.java Note: The last two applications are applets, and must be viewed either using a web brower or using the appletviewer application (e.g., using the command av RandomQuilt). Here are the required html files RandomQuilt.html | GraphData.html

Mar 29: Here are the lecture notes for chapter 12: chapter12.pdf

Mar 26: Here are the lecture notes for chapter 11: chapter11.pdf as well as the final demo program presented in class today: ExceptionHandling05.java

Mar 26: Marks for Test #2 now posted. Use the courseInfo command to view. (See note posted on March 2.) The tests will be handed back in class today.

Mar 24: Here are the programs presented in class today: DemoCharFreq.java | ExceptionHandling01.java | ExceptionHandling02.java | ExceptionHandling03.java | ExceptionHandling04.java

Mar 23: Click here for solutions to Test #2. (Note: marks will be posted soon.)

Mar 22: Here are the lecture notes for Chapter 10: chapter10.pdf as well as the demo program DemoWordFreq.java. The last slide in the notes presents the Programming Challenge discussed in class today. Please do this for Wednesday.

Mar 17: Here are demo programs and associated files presented in class today: DemoArrayList.java | DemoHashSet.java | DemoHashMap.java | sample.txt | GulliversTravels.txt | d1-wordfreq.txt. Note: The file d1-wordfreq.txt is derived from the British National Corpus. The sample contains 67,962,112 total words, or 9,022 unique words. You can read more about the British National Corpus from ftp://ftp.itri.bton.ac.uk/bnc/

Mar 15: Here are updates to DemoToolkit.java and DemoCalendar.java programs. For DemoToolkit, the last line of output identifies the class of the Toolkit object returned by the getDefaultToolkit() method of the Toolkit class. On my Windows XP system, it is sun.awt.windows.WToolkit. For homework, please execute this program in the Ariel lab and make a note of the output. We’ll discuss this in class on Wednesday.

Mar 12: I’d like to follow up on something discussed near the end of class today. We expected the following code…

Calendar c = Calendar.getInstance();

Date d = ((GregorianCalendar)c).getGregorianChange();

IO.println(d);

to generate a run-time error, but it didn’t. Why? I didn’t have an answer in class, but I do now. Here it is. First, note that getGregorianChange() is a method of the GregorianCalendar class, not of the Calendar class. In the code segment above, it appears that no GregorianCalendar object is created. The cast in the second line changes c into a GregorianCalendar reference, thus no compile error is generated, but the cast does not change memory: the object is still a Calendar object, or so it seems. So, a run-time error should occur in attempting to execute a GregorianCalendar method on the Calendar object. Right? Wrong! In fact, c is a reference to a GregorianCalendar object. The API for the getInstance() method states that it “gets a calendar using the default time zone and locale. The Calendar returned is based on the current time in the default time zone with the default locale.” So, it seems that the object created (on my computer at York University) is probably a GregorianCalendar object. This can be checked by adding the following line of code:

IO.println(“Class of c: “ + c.getClass());

Indeed, the class of c is identified as GregorianCalendar. Whew!

I’ll do a quick demo of this in class next week. See you on Sunday, and good luck.

Mar 10: Here are the lecture notes for Chapter 9: chapter09.pdf as well as the demo programs and files used for Chapter 9: DemoInstanceof.java | creditcards2.txt | DemoToolkit.java | DemoCalendar.java | DemoRectangle.java

Mar 5: Here are the lecture notes for Chapter 8: chapter08.pdf as well as the demo programs and files used for Chapter 8 DemoPortfolio.java | portfolio.txt | DemoGlobalCredit.java | creditcards.txt

Mar 3: Model answers to Test #1 are posted on red as /cs/home/wildes/1020/T1W2004/t1.txt. To view the answers, log on to red.cs.yorku.ca and issue the command

more /cs/home/wildes/1020/T1W2004/t1.txt

Mar 2: Marks for Test #1 now posted. Marks are posted using the department’s courseInfo service. To view your mark, logon and issue the command courseInfo 1020M

Mar 1: Here is the source code for the demo program presented in class today: DemoPortfolio.java. At the end of the source code, there is a programming challenge. Please modify the program, as requested. We’ll discuss the solution in class on Wednesday.

Feb 27: The slides for Chapter 7 (chapter07.pdf) and the ASCII code chart (ascii.gif) have been updated, as per our discussion in class today. Please update your files accordingly.

Feb 25: Here are the lecture notes for Chapter 7: chapter07.pdf as well as the demo programs used for Chapter 7: DemoStringArray.java | DemoEncrypt.java | DemoDecrypt.java | sample.txt

Feb 25: There was a fair bit of discussion in class today about ASCII codes. As I noted, ASCII is a 7-bit coding system for representing alphanumeric symbols, digits, punctuation symbols, and control codes. ASCII codes appear as the first 128 entries in the 16-bit Unicode coding system. Click here for an image showing the complete ASCII code chart. We’ll discuss this in class on Friday.

Feb 24: Note: The course evaluation for section M will take place Wednesday, March 31, 11:05 a.m.

Also, here is the Programming Challenge given in class today:

Programming Challenge. Rework the StringBackwards programming challenge using the StringBuffer class. Call the new program StringBackwards2.java.

Feb 11: Here are the programming challenges presented in class today. Please solve these for Friday’s class.

Programming Challenge #1. Write a program that creates a String object from a sequence of characters inputted from the keyboard and then creates a new String object consisting of the characters arranged backwards. Output the new string to the console. Call the program StringBackwards.java.

Programming Challenge #2. Write a program that inputs a word from the console and then checks to determine if the word is a palindrome. Output the result to the console. Call the program Palindrome.java. (Note: A palindrome is a word that is the same backwards as forwards; e.g., “toot”)

Jan 26: Here are the lecture notes for Chapter 4: chapter04.pdf

Jan 23: Here is the solution to today’s Programming Challenge: Mortgage03.java, as well as the demo programs presented in today’s class: Example07.java | Example08.java

Jan 22: Please note: There will be no class next Wednesday (Jan 28). I have an appointment for personal matters that, unfortunately, cannot be changed.

Jan 21: Here are the lecture notes for Chapter 3: chapter03.pdf as well as the source files for the demo programs: Mortgage01.java | Mortgage02.java | Example01.java | Example02.java | Example03.java | Example04.java | Example05.java | Example06.java. Please remember to work on the “Programming Challenge” given in class today. The problem description is in the last slide in the notes for Chapter 3. We’ll take up the solution on Friday.

Jan 16: Here are the lecture notes for Chapter 2: chapter02.pdf

Jan 12: An organizational meeting will be held this Thursday for students interested in the ACM Programming Contest. The meeting will be at 4:00 pm in CSB 3033. More information is available from http://www.cs.yorku.ca/acm/.

Jan 9: Here are the lecture notes for Chapter 1: chapter01.pdf

Jan 7: Please make sure you purchase the course text as soon as possible. Read chapter 1 immediately, and try to read chapter 2 before next week.

Dec 10: Announcements for Section M will be placed here.