Homework Assignment 4

Due: 9am, November 20, 2009.
No extensions -- if you are not finished then just hand in what you have completed.

The purpose of this assignment is to give you practice at writing Java code for:

Logical decisions and branching constructs,
Simple looping constructs,
Organization of program output into a tidy table.
One- and two-dimensional arrays.

Solve problems 18, 19, 21, 26, 27 and 28 in the Java Programming Exercises (Green Lecture Notes).

Points to note:

Problem 18
The method declarations:
```
    public double boxVolume( double height ) { ...
    public double boxSurfaceArea( double height ) { ....
```
will only work if you explicitly create a folded box object. We will cover that detail next week. In the meantime, you can compute the solution by avoiding objects and changing the method declarations to:
```
    static double boxVolume( double height ) { ...
    static double boxSurfaceArea( double height ) { ....
```
Otherwise, the program structure for your solution should be very similar to the wind force computation ( see WindForce.java ) on the java examples page.
Finally, your program output should be formatted into a tidy table. Both the old style of formatting (i.e., using DecimalFormat objects) and c-style of formatting (i.e., using System.out.printf()) will be acceptable.
Problem 21
Your solution should involve a loop with an if- else if - else embeded within. See, for example, the water flow computation for urban fire fighting.
Problem 26
One- and two-dimensional arrays are used to store the data in this problem.
There is a small typo -- the mass matrix declaration should read:
```
    double daMass [] = { 1.0, 1.0, ..... };
```
and not
```
    double daMass [][] = { 1.0, 1.0, ..... };
```
Sorry about that!
Problem 27
Part a can be computed using a two-dimensional array of integers. You should output the matrix in a tidy format. I suggest that you use the System.out.printf() method.
See "Java Handout 3" on page 128 of the green lecture notes for examples of printf's capabilities.
The output for part b is rather long -- hence, just hand in an abbreviated version of your program output.
Part c can be done on pencil and paper and is only 5-6 lines long. However, in order to get the points you should clealy articulate your reasoning that leads to the result.

Note. For each problem, hand in a copy of your program source code and a script of I/O for typical program usage.

If you are working on UNIX/Mac OS X then the procedure for creating a script is easy -- just type something like:

    prompt >> script output-file

Now all input/output on the screen will be echoed to the file "output-file". To terminate the script, type:

    prompt >> exit

Now print "output-file" and hand it in.

If you are working on Windows, just cut-and-paste the output into a Word document.