CSC207.01 2014S, Class 11: Exceptional Programming
==================================================

_Overview_

* Preliminaries.
    * Admin.
    * Upcoming work.
    * A few notes on recent assignments.
    * Questions.
* Lab.

Preliminaries
-------------

### Admin

* Thanks to Mr. Walker, we now have a copy of Weiss in the learning center.
* I've posted a new style for CSC207 to `/home/rebelsky/share/CSC207.xml`
    * It probably needs some more work, but I wanted to make some
      forward progress.
    * You should be able to copy the file, but I'll try to remember to post
      it on a Web page.
* Extra credit: 
    * Wednesday Extra, February 5 at 4:30 in 3821, AppDev
    * Convo Feb. 5 at 4:15 pm in JRC 101: Pussy Riot and Putin.
    * CS Table Friday: NP Completeness
    * More?
* Review session tomorrow at 10 a.m.

### Upcoming Work

* Readings for Monday: References and Autoboxing/Autounboxing.
    * Not yet written.
    * Probably available Saturday.
* Writeup due MONDAY.  We will continue today's lab on Friday.
    * Subject: CSC 207 Writeup 8: Exceptions (YOUR NAME)
* HW 3 due tonight.
* HW 4 posted in draft form.

### A Few Notes from Recent Labs

#### The `import` statement.

`import java.io.PrintWriter`

> Introduces a shorthand.  You can now refer to `PrintWriter` and the
  Java compiler knows that you mean `java.io.PrintWriter`.  (It's not
  clear that `import` does much more of use.)

`import java.io.*`

> A shorthand for importing everything from a package.  Sam discourages
  the use, because it makes it harder to figure out what classes come
  from where.

#### Copying Two Lines

* Many of you closed your PrintWriter and BufferedReader before the
  end of the program.  That's generally a bad idea - you might want
  to do some more output or input later.
* Many of you had a variable for each line that you read.  That seems
  inefficient.  

     line1 = fileEyes.readLine();
     line2 = fileEyes.readLine();
     filePen.println(line1);
     filePen.println(line2);

* Note that copying lines should really be a *loop*.
   
     private static final int NUMLINES = 2;
     ...
     for (int i = 0; i < NUMLINES; i++)
       {
         filePen.println(fileEyes.readLine());
       } // for

### Questions on HW3

_Can you explain the last test?_

    assertArrayEquals (new String[] { "a", "b", "c" },
                       StringUtils.splitCSV("a,b,c"));
    assertArrayEquals (new String[] { "a,b", "c" },
                       StringUtils.splitCSV("\"a,b\",c"));
    assertArrayEquals (new String[] { "a", "b,b\"", "c" },
                       StringUtils.splitCSV("a,\"b,b\"\"\",c"));

> Sure.  We start with the "conceptual units": We want to write a CSV line
that represents the three values [a], [b,b"], and [c].  (The square brackets
are there to clarify what the units are, they are not part of the units.)

> As we try to represent this in CSV, we realize that the middle entity
has a comma, so we need to put quotation marks around it.  `"b,b""`.  But
there's an internal quotation mark, so we need to double it. `"b,b"""`.

> Our CSV line is now `a,"b,b""",c`.

> We want to represent that as a C/Java string.  In C and Java, strings start
and end with double-quotation marks and any internal double-quotation marks must
be preceded by backslashes.  Hence, we get `"a,\"b,b\"\"\",c"`.  

> Wasn't that fun?  Learning to read C strings takes a bit of effort.

_How much detail should we put in end braces?_

> Enough that you can tell what you are ending.  For `if` statements, I tend
to prefer that you indicate something about the test, so that you can tell 
which brace ends which part of a nested if.

      } // if (x != 0)
    } // if x is valid

> Similarly, for a for loop, it's helpful if you indicate which loop variable
you are using

       } // for (j)
     } // for (i)

_Should we do unit tests for "The Name Game"?_

> Probably not.  An experiment sufficies.

Lab
---

Start the lab on Exceptions.  We'll continue it on Friday.