Java Reference
In-Depth Information
24. (You must complete Self-Check Problem 23 before answering this question.)
Add methods called setFirstName , setMiddleInitial ,and setLastName to your Name class. Give the param-
eters the same names as your fields, and use the this keyword in your solution.
25. How does encapsulation allow you to change the internal implementation of a class?
Section 8.5: Case Study: Designing a Stock Class
26. What is cohesion? How can you tell whether a class is cohesive?
27. Why didn't we choose to put the console I/O code into the Stock class?
28. Add accessor methods to the Stock class to return the stock's symbol, total shares, and total cost.
Exercises
1. Add the following method to the Point class:
public int manhattanDistance(Point other)
Returns the “Manhattan distance” between the current Point object and the given other Point object. The
Manhattan distance refers to the distance between two places if one can travel between them only by moving hori-
zontally or vertically, as though driving on the streets of Manhattan. In our case, the Manhattan distance is the sum
of the absolute values of the differences in their coordinates; in other words, the difference in x plus the difference in
y between the points.
2. Add the following method to the Point class:
public boolean isVertical(Point other)
Returns true if the given Point lines up vertically with this Point , that is, if their x -coordinates are the same.
3. Add the following method to the Point class:
public double slope(Point other)
Returns the slope of the line drawn between this Point and the given other Point . Use the formula ( y 2 - y 1 ) / ( x 2 - x 1 )
to determine the slope between two points ( x 1 , y 1 ) and ( x 2 , y 2 ). Note that this formula fails for points with identical
x -coordinates, so throw an IllegalArgumentException in this case.
4. Add the following method to the Point class:
public boolean isCollinear(Point p1, Point p2)
Returns whether this Point is collinear with the given two other Point s. Point s are collinear if a straight line can be
drawn that connects them. Two basic examples are three points that have the same x - or y -coordinate. The more gen-
eral case can be determined by calculating the slope of the line between each pair of points and checking whether this
slope is the same for all pairs of points. Use the formula ( y 2 - y 1 ) / ( x 2 - x 1 ) to determine the slope between two points
( x 1 , y 1 ) and ( x 2 , y 2 ). (Note that this formula fails for points with identical x -coordinates so this will have to be a special
case in your code.) Since Java's double type is imprecise, round all slope values to a reasonable accuracy such as
four digits past the decimal point before you compare them.
5. Add the following method to the TimeSpan class:
public void add(TimeSpan span)
Adds the given amount of time to this time span.
 
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