exercise-answers.md

CSE 143

Exercise Answers

Week 7

1. Comparable class, 20 points. BookData.

   public class BookData implements Comparable<BookData> {
   	private String title;
   	private String author;
   	private int reviews;
   	private double total;
   
   	public BookData(String title, String author) {
   		this.title = title;
   		this.author = author;
   		this.reviews = 0;
   		this.total = 0.0;
   	}
   
   	public void review(double rating) {
   		reviews++;
   		total += rating;
   	}
   
   	public String getTitle() {
   		return title;
   	}
   
   	public double getRating() {
   		if (reviews == 0)
   			return 0.0;
   		else
   			return total / reviews;
   	}
   
   	public String toString() {
   		double rating = (int) (10.0 * getRating()) / 10.0;
   		String result = title + ", by " + author + ", " + rating + " (";
   		if (reviews == 1)
   			result += "1 review)";
   		else
   			result += reviews + " reviews)";
   		return result;
   	}
   
   	public int compareTo(BookData other) {
   		double delta = other.getRating() - getRating();
   		if (delta < 0)
   			return -1;
   		else if (delta > 0)
   			return 1;
   		else // delta == 0
   			return other.reviews - reviews;
   	}
   }

2. Comparable class, 20 points. Office.

   public class Office implements Comparable<Office> {
   	private double width;
   	private double length;
   	private boolean couch;
   	private int windows;
   
   	public Office(double width, double length, boolean couch, int windows) {
   		this.width = width;
   		this.length = length;
   		this.couch = couch;
   		this.windows = windows;
   	}
   
   	public boolean isCorner() {
   		return width == length && windows == 2;
   	}
   
   	public String toString() {
   		String output = "width: " + width + ", length: " + length + ", windows: " + windows;
   		if (couch) {
   		output += ", has a couch";
   		}
   		return output;
   	}
   
   	public int compareTo(Office other) {
   		double area = width * length;
   		double otherArea = other.width * other.length;
   		if (area == otherArea) {
   			if (windows != other.windows) {
   				return other.windows - windows;
   			} else {
   				if (couch && !other.couch) {
   					return -1;
   				} else if (!couch && other.couch) {
   					return 1;
   				} else {
   					return 0;
   			}
   		}
   		} else if (area > otherArea) {
   			return -1;
   		} else {
   			return 1;
   		}   
   	}
   }