CSSE 220 – Object-Oriented Software Development

Homework 7

Objectives

Practice creating, documenting, and testing classes based on a given public interface. More graphics and math practice. Practice formatting text.

Tasks

1. Complete the assigned reading for the next session: Big Java Chapter 5.
   • Pay particular attention to the §5.2 on Comparing Values and §5.5 on Test Coverage.
   • Be sure to read Advanced Topics 5.1-Selection Operator (on page 187), 5.2-switch Statement (on pp. 197-198), and 5.3-Enumerated Types (on page 204).
   • As you read, see if you can answer the self-check questions.
   • Bring your questions to class!
2. Complete the assessment exercise over this reading on ANGEL (under Lessons → Assignments).
3. Programming:

   1. In Eclipse, checkout the FundamentalDataTypes project.

      • Use the SVN Repositories view to check out this project.

   2. Using a for loop and the charAt() method of String, complete the four TODO items in the StringsAndChars class.
   3. Edit the main() method of ScannerExample to print appropriate prompts for the user.

   4. • Mutchler's section only: Finish the Faces project if you can. But don't get stuck — bring your questions to the evening assistants, me in my office, or class the next day.
      • Boutell's section only: Create a class CubicPlot. Its constructor should take eight (yes, eight!) arguments:
        • top, left — the top-left coordinates for a rectangle on which the class will plot
        • width, height — the width and height of the rectangle on which the class will plot
        • a, b, c, d — the coefficients of the equation y = ax³ + bx² + cx + d, that the class will plot

        The class should include a method drawOn(Graphics2D g) that plots the graph as detailed below. The classes CubicPlotViewer and PlotComponent are provided. In PlotComponent, uncomment the call of the CubicPlot’s constructor that we supplied to test your code.

        1. The origin of the plotted graph should be in the center of the rectangle described by top, left, width, and height.
        2. The plotted graph should display x- and y-axes. You do not need to include tick marks on the axes.
        3. Use String’s format() method and Graphics2D’s drawString() method to display the equation on the graph.
        4. (Due with HW8) Use a loop to calculate the y value for each integer x from -width to width. Plot the graph by drawing a line from the previous point calculated to the next point. (You’ll have to calculate the first point outside the loop.) Be sure to shift your plot according to the required origin. You should also “flip” the y values when plotting so that the y-axis increases up the screen.
        5. Bonus: clip the plot so that it doesn’t extend beyond the bounds given by top, left, width, and height.

        The figure below gives an example plot (without clipping, no bonus for me):

Turn-in Instructions

Turn in your programming work by committing it to your SVN repository.