Lab 3: More Java Strings

Today, you'll continue with some more word games. You'll also be introduced to Mercurial, a tool for managing the different versions that you make of files. Take a few minutes to read the page about Mercurial; what is there will make more sense as you work through the lab.

I. Setting up

For a starting point, clone the repository I have provided. The cloning process will create a new directory, so change into the directory where you want it to be created. Then

$ hg clone /cslab/class/csci235/lab3 

That will make a lab3 directory, which will include both a working copy and a directory. Change into that directory.

The presence of the repository is normally invisible. If you do ls, you won't see anything but one Java source file. However, if you give the -a (for all) option to ls, it will show you the filenames that start with dots. You should see a couple that start with .hg.

You can check the status of your working copy with

$ hg status

That won't tell you much right now, because you haven't done anything. But fire up your editor and make an awful mess of Palindrome.java, being sure you save the results. If you try the status command again, the file will be flagged as "modified". Now try

$ hg revert Palindrome.java

If you want to use your code from the last lab as a starting point, you can. Just copy Palindrome.java from your account to this directory. (Do you remember how?) Then, since you want that to be in the repository, commit it with

$ hg commit -m "Palindrome.java from my lab 2"

II. Pangrams

Your previous program tests whether a string is a palindrome. Now you'll tackle another word game.

A sentence is a pangram if it contains every letter of the alphabet at least once. Examples include

• My faxed joke won a pager in the cable TV quiz show.
• The quick brown fox jumps over the lazy dog.
• Pack my box with five dozen liquor jugs.

Write a program which prompts the user for a string and determines whether or not that string is a pangram. Ignore spaces, punctuation, and capitalization. Your program should also include an opening documentation block (following the style we've seen in class) and a comment on every variable you declare.

Note: a good way to start would be to copy your palindrome program. You can do that with

$ hg copy Palindrome.java Pangram.java

You use the "hg copy" command (instead of plain cp) so that the repository will know that your new file is derived from the old one.

If you create a new file (Silly.java, say) that you want the repository to track, you use the command

$ hg add Silly.java

Hint: Think about how you would do this using pencil and paper. You can do this using the methods listed in the textbook, which are also in the simplified online documentation. Need a hint? Another?

Feel free to commit your changes at any time that you have something you might want to go back to. To commit, think of a brief description/label for the state you are about to commit. Then the command

$ hg commit -m "message"

You can revert the state of a file to its last committed state with

$ hg revert filename

(It is also possible to revert to an earlier committed state, but that is a bit more complicated.)

When you are satsified that you have completed part II, commit with the message "finished part II".

III. Anagrams

Two words or phrases are anagrams of each other if they contain all the same letters (with the same frequency). Examples include

• dormitory - dirty room
• the Morse code - here come dots
• eleven plus two - twelve plus one
• Wheaton College - Leech ate long. Ow!

Write a program Anagrams.java that prompts the user for two strings. Test whether the two strings are anagrams of each other. Ignore spaces, punctuation, and capitalization. Your program should also include an opening documentation block (following the style we've seen in class) and a comment on every variable you declare.

Again, you might want to copy one of your other programs to get a starting point. Don't forget to add your file to the repository and commit (at least) the final version.

Turning it in

Make a script file that shows you compiling your programs and running them with inputs that make it clear that they work correctly. (See how to script.)

Print your two .java files and the script. (See how to print.)

Use handin to hand in the files as lab3, too. (See how to do that, too.)

Copying a repository

There are special ways to copy a directory with a Mercurial repository. If user msnerd wants to copy from the lab account to directory csci235/lab3 under his home directory, the command would be

$ hg clone . ssh://msnerd@cslab25/csci235/lab3

You'll be prompted for your password, perhaps twice.

When you have logged in to your account and changed into your csci235/lab3 directory, all that will be there is the repository. To set up the working copy, you use

$ hg update