This IS a pair assignment. You MUST do the assignment with your partner.
You must complete an interview
with a Lab Tutor for this PSA. Interviews are individual (partly to
ensure that one partner doesn't do all the work). See instructions here for more details.
This work should be done in its own directory called 'psa6'. Instructions here.
This assignment has sample solution code that you can run on ieng6. You won't be able to see the java code itself =) but you will be able to do tests to see what it does, and make sure yours does the same thing. YOUR CODE MUST DO THE EXACT SAME THING. EXACT!! Wording, spaces, everything. Instructions on how to run the sample solution code are here .
Each file must have a header with the team members' names, logins, and PIDs. The header should also describe the program in 2-3 sentences.
This homework requires skills from Chapter 1 through Chapter 4 (objects), and 6.1 (arrays).
Problem 1
Write a program to keep track of contacts in a cell phone.
Introduction:
Your code is for a really cheap cell phone that only has enough space to store at most 10 entries in the contact list.
Offer the user the following menu of options:
bash-2.05b$ java ContactsList
Please choose (enter choice in upper case only):
(A)dd new contact
(D)elete contact
(C)hange phone number for contact
(P)rint contacts
(Q)uit
If the user chooses to add a new contact, input the name of the person and the phone number, and add the entry. You should keep them in order of when they were added (oldest to newest). Remember that there can be at most 10 entries.
If the user chooses to delete a contact, input the name of the person to remove, and remove the entry.
If the user chooses to change a number, input the name of the person whose number is changing, and update the entry.
If the user chooses to print contacts, print all the contacts (name and number) in order of when they were added (oldest to newest).
Keep returning to the main menu after each operation, until the user chooses to quit.
Details:
Your program must be in a file called ContactsList.java
The user should enter the phone number as an integer, i.e. do NOT include formating such as parentheses and dashes. Also, do NOT include area code. So (858)534-3362 should be entered as 5343362.
You should be able to store the name including first and last name, maybe a middle name, maybe more, etc (read in whole line of input for the name).
You must implement your contact list as two arrays: an array of Strings to hold the names, and an array of int to hold the numbers. Remember that you should store at most 10 entries.
There are some things you should try on the sample solution, so you can get the correct message to print to the user in those cases:
Of course, each menu option in standard usage.
Adding when there are already 10 entries.
Changing or deleting when there are 0 entries.
Changing or deleting and the name entered does not match any name.
Printing when there are 0 entries.
Added 1/15/07: Selection from the main menu that is not a legal option.
Maybe you are wondering, what if the user chooses to add two contacts with the same name? I tried this on my actual cell phone and it doesn't complain. So don't do anything special in this case. What should you do if the user wants to change or delete and enters that name? Change or delete only the first one (again, ordered by when they were added, oldest to newest).
Added 1/15/07: You can assume the user enters something each time user input is required (so checking the first character of the input will always be safe because there will always be at least one letter). However, the user may not enter a valid menu choice (they may type a word that starts with a letter other than A/D/C/P/Q). You can also assume that the user enters an integer for the phone number.
Hints:
Make sure to maintain the oldest-to-newest ordering when you delete something from the middle.
A good design for managing these two different arrays would be to have them "match" (so the 3rd phone number in the phone number array belongs to the 3rd name in the name array).
Problem 2
Write a program that shows an animated demonstration of Galileo's famous Leaning Tower of Pisa experiment, with the wrong outcome.
Introduction:
Galileo is considered by many to be a founder of experiment-based science and the scientific method. He famously (though perhaps only in legend) dropped two objects, one heavy and one light, from the Leaning Tower of Pisa. This was to test whether the heavy one would fall faster. Counterintuitively, it does not. They accelerate at the same rate and land at the same time.
You will make an animated demonstration of this famous experiment, but showing the wrong outcome. You will show the heavy item (represented as a larger item--we'll forget wind resistance for now) falling faster than the light item.
Details:
Important: This is another graphics problem, like the Turtle in PSA 4. So you will probably want to work mostly in the lab instead of from home. Refer to the PSA 4 description and webboard posts for how to get X-11 forwarding working, and so on.
First, you need to make a class Circle that draws circles (which will be used to make the two balls to be dropped). We have done most of the work for you. Copy the starter code (-bash2.05$ cp ~/../public/Circle.java ~/psa6/) then just add an instance method called "fall" that takes one argument, the distance to fall (an integer). It does not return any value. It should be a public method. It should cause the ball to move down the screen by the amount given in the distance parameter. (Big hint: you can implement this in just one line of code by calling one of the other methods in the Circle class)
Now, make a separate class that will use your Circle class. This class is in a file called GalileoUhoh.java. Again, we have provided some starter code (-bash2.05$ cp ~/../public/GalileoUhoh.java ~/psa6/).
In GalileoUhoh, we have already set up the animation window and drawn the Leaning Tower of Pisa. You need to place the two balls so that they are just over the edge of the top of the tower (where Galileo would be holding them, but he is not visible). It is very important to the experiment that the bottoms of the two balls are at the same height (not the centers), like so:
The large ball is blue and has radius 10 and the small ball is red and has radius 5. To set the color, use "Color.blue" or "Color.red" in your calls to the Circle class constructor.
You need to locate them so that the small ball, which is closest to the tower, just grazes the tower but never intersects it, as it falls straight down. The large ball is next to the small ball, and it should be as close as possible to the small ball, but far enough that they could never intersect either. The location of the top right point of the tower (near the red ball's start location) is (x,y) = (70,80). Remember that in Java graphics, (0,0) is the TOP LEFT corner, not the bottom left as you would typically have in graphs in math class. The y values increase as you go DOWN, and the x values increase as you go RIGHT.
Getting the balls correctly placed in their initial spots is the trickiest part. Now you just need to make them move down. Call the Circle class fall() method that you implemented to make the balls fall until each hits the ground. The large ball falls 10 units per 1/2 second and the small ball falls 5 units per 1/2 second. To make the computer pause for 1/2 second, add this line of code in your loop (move both balls, then call this once): try {Thread.sleep(500);} catch (Exception ex) {} (copy and paste exactly as you see here). Here is what they look like while falling and where they should end:
Note: There was an issue with the first version of the GalileoUhoh.java starter code not displaying the Leaning Tower of Pisa. If yours doesn't, you can get the new fixed version by doing the same "cp" command.
-
WOW! After you are done with the basic assignment, follow these simple instructions (just copying a different version of the starter code and a couple other files into your directory) to make your program look like this! (optional -- not graded)
Start by creating a directory (folder) in your ieng6 cs8fzz
account (this is necessary for the bundle-psa4 script). After you log
in, create a directory by typing the commands:
-bash-2.05b$ mkdir psa6
Go into that directory (like double clicking to open a folder) with
the command:
-bash-2.05b$ cd psa6
Note: you must name
your directories (folders) and files as indicated in the problem
descriptions for the turn in program to work.
1 Point: For proper formatting. Your code is properly and consistently indented.
1 Point: For documentation. You must write a 2-4 sentence description of the program (as a comment) that provides insight into what the program does and what it's useful for. In this header comment, you are also required to put the author names, author PIDs and author logins
1 point: Correctly handle user interaction, matching sample solution (print correct messages, continue program until quit, etc)
GalileoUhoh.java (6 pts):
2 points: Correctly draw large blue ball in start position.
2 points: Correctly draw small red ball in start position.
2 points: Correctly animate balls.
Circle.java (2 pts):
2 points: Correctly add "fall" method.
How to turn in your homework electronically
When you are ready to turn in your homework, run bundle-psa4
from your psa4 directory. The session should look like
this:
-bash-2.05b$ cd ~/psa6
-bash-2.05b$ bundle-psa6
Good; all required files are present:
ContactsList.java
Circle.java
GalileoUhoh.java
Do you want to go ahead and turnin these files? [y/n]y
OK. Proceeding.
Performing turnin of approx. XXXX bytes
Copying to /home/linux/ieng6/cs8w/turnin.dest/cs8wzz.psa6
.
Done.
Total bytes written: XXXX
Please check to be sure that's reasonable.
Turnin successful.
If you want to make changes after you've turned
in your homework, make the changes and run bundle-psa6
again. The program will warn you that a "previously turned-in
file exists" and ask if "you wish to over-write this
existing file" (delete the old version and replace it with this
new one). Respond in the affirmative by typing y and
pressing the Enter key.
10% of your grade on this assignment will come from an interview you will have with one of the tutors during Open Lab Hours. You have 48 weekday hours after the electronic turnin deadline to get your interview done. The deadline for the interview for PSA 5 is Monday, Feb 19, theoretically at midnight, but actually by the end of the last tutor hour scheduled.
You get an interview by going into B260 during a scheduled tutor hour. Find the tutor, ask them if you can interview for PSA 5. If they have others who are waiting for interviews, your name will go on the end of the list of people waiting. Interviews take about 5 minutes each. It is your responsibility to go in early enough that you can get your interview completed. If everyone waits until the last hour on Wed, this will not work.
The tutor will ask you to log in, change to the directory where your work is (psa6) and then to follow their directions. They will ask you to run your program to show that it works, open files in your favorite editor, and ask you questions about how your code works. Additionally, they may question you as to how you would (theoretically) make small changes to the program to have it do something slightly different.
Learning to be able to explain your problem solving process and discuss code with another human being is a very important professional skill. We hope that this process will help you develop this skill.
Copying the assignment directory to partner's home directory
You can copy the psa6 directory and its files to your partner's home directory by:
bash% scp -r psa6 cs8wxx@ieng6.ucsd.edu:
(don't forget the colon at the end of the command) where cs8wxx is your partner's username. You must be in the parent directory of the psa4 directory. So, you if you are currently in the psa4 directory you should execute "cd ..". Similarly, if the psa6 direcory is in your home directory then you have to be in your home directory. If you aren't there just execute "cd ~" and you'll be there. Your partner is required to enter his password when you enter the scp command.
To check if the copy worked, your partner must login and ckeck if the psa6 directory exists in his home directory and if the proper files are located in it. This can be done by executing: "ls ~/psa6". The files in the psa4 directory should be listed.
Redirecting the input and the output
You can redirect the input af a program by using the "<" symbol in the command line. Instead of reading the input from the standar input device (which is the keyboard):
bash% java MyProgram < sampleEmail.txt
This command will redirect the input of the MyProgram program to the file sampleEmail.txt. It will read the contents of the file as if they were given by pressing the buttons on keyboard.
Similarly you can redirect the output af a program by using the ">" symbol in the command line. Instead of displaying the output on the standar output device (which is the computer monitor):
bash% java MyProgram > outFile.txt
This command will redirect the output of the MyProgram program to the file sampleEmail.txt. It will write the output in the "outFile.txt" file (all contents of the will be erased if file exists, if it doesn't exist, it will be created) as if they would be printed on the computer screen (so, you won't get any output on the screen).
You can combine both redirections. For example you may have an email.txt file with a sample email, and also you want the results of the scan to be put on the file output.txt. This can be done by:
bash% java MyProgram < email.txt > output.txt
Finding the differences between files
You can find the differences between two text files by using the diff command:
bash% diff filename1 filename2
The output will be the differences between the files. If there is no output at all that means that the files are identical.
Example: Testing the output of your program, can be completed in four steps, using the above tips.
Create a file with sample input (lets name it "input.txt" for your program (as if you would write it if the program was running)
Run your program and redirect the exit to a file: bash% java Statistics < input.txt > output1.txt
Run the provided program and redirect the exit to a second file: bash% runsample Statistics < input.txt > output2.txt
Check if there are differences between the two output files: bash% diff output1.txt output2.txt
Learning to use text editors
Vim
Run the command vimtutor, a separate program that will
teach you to use Vim.
Emacs
Use the built-in tutorial by running emacs and, within
the editor, typing CTRL-h t.
Pico
You can reach Pico's built-in help by typing CTRL-g. If
you want further instruction, look at this Pico
tutorial from NC State.
Use a real picture of the Leaning Tower of Pisa!
After you are done with the basic GalileoUhoh.java assignment, follow these simple instructions:
Make a new directory called psa6bonus: -bash2.05$ cd -bash2.05$ mkdir psa6bonus -bash2.05$ cd psa6bonus
Copy a different version of the GalieloUhoh.java starter code into your directory: -bash2.05$ cp ~/../public/GalileoUhohBonus.java ~/psa6bonus
Copy your Circle.java class (including the fall() method you added) into the psa6bonus directory: -bash2.05$ cp ~/psa6/Circle.java ~/psa6bonus/
Open your original GalileoUhoh.java and copy the code that you added to that file. Paste it into the new one (GalileoUhohBonus.java) in the same place. The only thing different in the starter code is inside the "GUI stuff you can ignore" part at the top (and we changed the class name). So your part of the code should work just the same.
Copy two files into your psa6bonus directory: -bash2.05$ cp ~/../public/GraphicsUtil.class ~/psa6bonus/ -bash2.05$ cp ~/../public/LTP.gif ~/psa6bonus/
Compile everything at once by doing: -bash2.05$ javac *.java
Note: To run it, you do something just slightly different than normal (note the extra part in bold): -bash2.05$ java -cp . GalileoUhohBonus
