java语言程序设计基础篇第十版第十三章练习答案讲课讲稿.docx

1、java语言程序设计基础篇第十版第十三章练习答案讲课讲稿java语言程序设计基础篇第十版第十三章练习答案01public class Exercise13_01 public static void main(String args) TriangleNew triangle = new TriangleNew(1, 1.5, 1); triangle.setColor(yellow); triangle.setFilled(true); System.out.println(triangle); System.out.println(The area is + triangle.getAre

2、a(); System.out.println(The perimeter is + triangle.getPerimeter(); System.out.println(triangle); class TriangleNew extends GeometricObject private double side1 = 1.0, side2 = 1.0, side3 = 1.0; /* Constructor */ public TriangleNew() /* Constructor */ public TriangleNew(double side1, double side2, do

3、uble side3) this.side1 = side1; this.side2 = side2; this.side3 = side3; /* Implement the abstract method findArea in GeometricObject */ public double getArea() double s = (side1 + side2 + side3) / 2; return Math.sqrt(s * (s - side1) * (s - side2) * (s - side3); /* Implement the abstract method findC

4、ircumference in * GeometricObject */ public double getPerimeter() return side1 + side2 + side3; Override public String toString() / Implement it to return the three sides return TriangleNew: side1 = + side1 + side2 = + side2 + side3 = + side3; 02import java.util.ArrayList;public class Exercise13_02

5、public static void main(String args) ArrayList list = new ArrayList(); list.add(14); list.add(24); list.add(4); list.add(42); list.add(5); shuffle(list); for (int i = 0; i list.size(); i+) System.out.print(list.get(i) + ); public static void shuffle(ArrayList list) for (int i = 0; i list.size() - 1;

6、 i+) int index = (int)(Math.random() * list.size(); Number temp = list.get(i); list.set(i, list.get(index); list.set(index, temp); 03import java.util.ArrayList;public class Exercise13_03 public static void main(String args) ArrayList list = new ArrayList(); list.add(14); list.add(24); list.add(4); l

7、ist.add(42); list.add(5); sort(list); for (int i = 0; i list.size(); i+) System.out.print(list.get(i) + ); public static void sort(ArrayList list) for (int i = 0; i list.size() - 1; i+) / Find the minimum in the listi.list.length-1 Number currentMin = list.get(i); int currentMinIndex = i; for (int j

8、 = i + 1; j list.get(j).doubleValue() currentMin = list.get(j); currentMinIndex = j; / Swap list.get(i) with list.get(currentMinIndex) if necessary; if (currentMinIndex != i) list.set(currentMinIndex, list.get(i); list.set(i, currentMin); 04import java.util.*;public class Exercise13_04 static MyCale

9、ndar calendar = new MyCalendar(); public static void main(String args) int month = calendar.get(MyCalendar.MONTH) + 1; int year = calendar.get(MyCalendar.YEAR); if (args.length 2) System.out.println(Usage java Exercise13_04 month year); else if (args.length = 2) /use user-defined month and year year

10、 = Integer.parseInt(args1); month = Integer.parseInt(args0); calendar.set(Calendar.YEAR, year); calendar.set(Calendar.MONTH, month - 1); else if (args.length = 1) /use user-defined month for the current year month = Integer.parseInt(args0); calendar.set(Calendar.MONTH, month-1); /set date to the fir

11、st day in a month calendar.set(Calendar.DATE, 1); /print calendar for the month printMonth(year, month); static void printMonth(int year, int month) /get start day of the week for the first date in the month int startDay = getStartDay(); /get number of days in the month int numOfDaysInMonth = calend

12、ar.daysInMonth(); /print headings printMonthTitle(year, month); /print body printMonthBody(startDay, numOfDaysInMonth); static int getStartDay() return calendar.get(Calendar.DAY_OF_WEEK); static void printMonthBody(int startDay, int numOfDaysInMonth) /print padding space before the first day of the

13、month int i = 0; for (i = 0; i startDay-1; i+) System.out.print( ); for (i = 1; i = numOfDaysInMonth; i+) if (i 10) System.out.print( +i); else System.out.print( +i); if (i + startDay - 1) % 7 = 0) System.out.println(); System.out.println(); static void printMonthTitle(int year, int month) System.ou

14、t.println( +calendar.getMonthName()+, +year); System.out.println(-); System.out.println( Sun Mon Tue Wed Thu Fri Sat); 05public class Exercise13_05 / Main method public static void main(String args) / Create two comparable circles Circle1 circle1 = new Circle1(5); Circle1 circle2 = new Circle1(4); /

15、 Display the max circle Circle1 circle = (Circle1) GeometricObject1.max(circle1, circle2); System.out.println(The max circles radius is + circle.getRadius(); System.out.println(circle); abstract class GeometricObject1 implements Comparable protected String color; protected double weight; / Default c

16、onstruct protected GeometricObject1() color = white; weight = 1.0; / Construct a geometric object protected GeometricObject1(String color, double weight) this.color = color; this.weight = weight; / Getter method for color public String getColor() return color; / Setter method for color public void s

17、etColor(String color) this.color = color; / Getter method for weight public double getWeight() return weight; / Setter method for weight public void setWeight(double weight) this.weight = weight; / Abstract method public abstract double getArea(); / Abstract method public abstract double getPerimete

18、r(); public int compareTo(GeometricObject1 o) if (getArea() 0) return o1; else return o2; / Circle.java: The circle class that extends GeometricObjectclass Circle1 extends GeometricObject1 protected double radius; / Default constructor public Circle1() this(1.0, white, 1.0); / Construct circle with

19、specified radius public Circle1(double radius) super(white, 1.0); this.radius = radius; / Construct a circle with specified radius, weight, and color public Circle1(double radius, String color, double weight) super(color, weight); this.radius = radius; / Getter method for radius public double getRad

20、ius() return radius; / Setter method for radius public void setRadius(double radius) this.radius = radius; / Implement the findArea method defined in GeometricObject public double getArea() return radius * radius * Math.PI; / Implement the findPerimeter method defined in GeometricObject public doubl

21、e getPerimeter() return 2 * radius * Math.PI; / Override the equals() method defined in the Object class public boolean equals(Circle1 circle) return this.radius = circle.getRadius(); Override public String toString() return Circle radius = + radius; Override public int compareTo(GeometricObject1 o)

22、 if (getRadius() (Circle1) o).getRadius() return 1; else if (getRadius() (Circle1) o).getRadius() return -1; else return 0; 06public class Exercise13_06 / Main method public static void main(String args) / Create two comarable rectangles ComparableCircle circle1 = new ComparableCircle(5); Comparable

23、Circle circle2 = new ComparableCircle(15); / Display the max rect ComparableCircle circle3 = (ComparableCircle)Max.max(circle1, circle2); System.out.println(The max circles radius is + circle3.getRadius(); System.out.println(circle3); class ComparableCircle extends Circle implements Comparable /* Co

24、nstruct a ComparableRectangle with specified properties */ public ComparableCircle(double radius) super(radius); Override public int compareTo(ComparableCircle o) if (getRadius() o.getRadius() return 1; else if (getRadius() 0) return o1; else return o2; 07public class Exercise13_07 public static voi

25、d main(String args) GeometricObject objects = new Square(2), new Circle(5), new Square(5), new Rectangle(3, 4), new Square(4.5); for (int i = 0; i objects.length; i+) System.out.println(Area is + objectsi.getArea(); if (objectsi instanceof Colorable) (Colorable)objectsi).howToColor(); interface Colo

26、rable void howToColor();class Square extends GeometricObject implements Colorable private double side; public Square(double side) this.side = side; Override public void howToColor() System.out.println(Color all four sides); Override public double getArea() return side * side; Override public double

27、getPerimeter() return 4 * side; 08import java.util.ArrayList;public class Exercise13_08 public static void main(String args) MyStack1 stack = new MyStack1(); stack.push(S1); stack.push(S2); stack.push(S); MyStack1 stack2 = (MyStack1) (stack.clone(); stack2.push(S1); stack2.push(S2); stack2.push(S); System.out.println(stack.getSize(); System.out.println(stack2.getSize(); class MyStack1 implements Cloneable private ArrayListO