Java语言程序设计-基础篇-第八版-第八章

package chapter8对象和类;

public class Circle2 {
double radius;
static int numberOfObjects = 0;

Circle2() {
radius = 1.0;
numberOfObjects++;
}

Circle2(double newRadius) {
radius = newRadius;
numberOfObjects++;
}

static int getNumberOfObject() {
return numberOfObjects;
}

double getArea() {
return radius * radius * Math.PI;
}

}

package chapter8对象和类;

public class Circle2 {
double radius;
static int numberOfObjects = 0;

Circle2() {
radius = 1.0;
numberOfObjects++;
}

Circle2(double newRadius) {
radius = newRadius;
numberOfObjects++;
}

static int getNumberOfObject() {
return numberOfObjects;
}

double getArea() {
return radius * radius * Math.PI;
}

}

package chapter8对象和类;

import javax.swing.*;

public class GUIComponents {
public static void main(String[] args) {
JButton jbtOK = new JButton("Ok");
JButton jbtCancel = new JButton("Cancel");
JLabel jlbName = new JLabel("Enter your name: ");
JTextField jtfName = new JTextField("Type Name Here");
JCheckBox jchkBold = new JCheckBox("Bold");
JCheckBox jchkItalic = new JCheckBox("Italic");
JRadioButton jrbRed = new JRadioButton("Red");
JRadioButton jrbyellow = new JRadioButton("Yellow");
JComboBox jcboColor = new JComboBox(new String[] { "Freshman",
"Sophomore", "Junior", "Senior" });

JPanel panel = new JPanel();
panel.add(jbtOK);
panel.add(jbtCancel);
panel.add(jlbName);
panel.add(jtfName);
panel.add(jchkBold);
panel.add(jchkItalic);
panel.add(jrbRed);
panel.add(jrbyellow);
panel.add(jcboColor);

JFrame frame = new JFrame();
frame.add(panel);
frame.setTitle("Show GUI Components");
frame.setSize(450, 100);
frame.setLocation(200, 100);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setVisible(true);
}

}

package chapter8对象和类;

public class TestCircle1 {
public static void main(String[] args) {

Circle1 myCircle = new Circle1(5.0);
System.out.println("The area of the circle of radius "
+ myCircle.radius + " is " + myCircle.getArea());

Circle1 yourCircle = new Circle1();
System.out.println("The area of the circle of radius "
+ yourCircle.radius + " is " + yourCircle.getArea());

yourCircle.radius = 100;
System.out.println("The area of the circe of radius "
+ yourCircle.radius + " is " + yourCircle.getArea());
}
}

class Circle1 {
double radius;

Circle1() {
radius = 1.0;
}

Circle1(double newRadius) {
radius = newRadius;
}

double getArea() {
return radius * radius * Math.PI;
}
}

package chapter8对象和类;

public class TestCircle2 {
@SuppressWarnings("static-access")
public static void main(String[] args) {
System.out.println("Before creating objects");
System.out.println("The number of Circle objects is "
+ Circle2.numberOfObjects);

Circle2 c1 = new Circle2();

System.out.println("\nAfter creating c1");
System.out
.println("c1: radius(" + c1.radius
+ ") and number of Circle objects ("
+ c1.numberOfObjects + ")");

Circle2 c2 = new Circle2(5);
c1.radius = 9;

System.out.println("\nAfter creating c2 and modifying c1");
System.out
.println("c1: radius (" + c1.radius
+ ") and number of Circle objects ("
+ c1.numberOfObjects + ")");

System.out
.println("c2: radius (" + c2.radius
+ ") and number of Circle objects ("
+ c2.numberOfObjects + ")");
}
}

package chapter8对象和类;

public class TestCircle3 {
public static void main(String[] args) {
Circle3 myCircle = new Circle3(5.0);
System.out.println("The ares of the circle of radius "
+ myCircle.getRadius() + " is " + myCircle.getArea());

myCircle.setRadius(myCircle.getRadius() * 1.1);

System.out.println("The area of the circle of radius "
+ myCircle.getRadius() + " is " + myCircle.getArea());

System.out.println(Circle3.getNumberOfObjects());
}
}

package chapter8对象和类;

import javax.swing.*;

public class TestFrame {
public static void main(String[] args) {
JFrame frame1 = new JFrame();
frame1.setTitle("Window 1");
frame1.setSize(200, 150);
frame1.setLocation(200, 100);
frame1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame1.setVisible(true);

JFrame frame2 = new JFrame();
frame2.setTitle("Window 2");
frame2.setSize(200, 150);
frame2.setLocation(410, 100);
frame2.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame2.setVisible(true);

}
}

package chapter8对象和类;

public class TestTV {
public static void main(String[] args) {
TV tv1 = new TV();
tv1.turnOn();
tv1.setChannel(30);
tv1.setvolume(3);

TV tv2 = new TV();
tv2.turnOn();
tv2.channelUp();
tv2.channelUp();
tv2.volumeUp();

System.out.println("tv1's channel is " + tv1.channel
+ " and volume level is " + tv1.volumeLevel);
System.out.println("tv2's channel is " + tv2.channel
+ " and volume level is " + tv2.volumeLevel);
}

}

package chapter8对象和类;

public class TotalArea {
public static void main(String[] args) {
Circle3[] circleArray;

circleArray = createCircleArray();

printCircleArray(circleArray);
}

public static Circle3[] createCircleArray() {
Circle3[] circleArray = new Circle3[5];

for (int i = 0; i < circleArray.length; i++) {
circleArray[i] = new Circle3(Math.random() * 100);
}
return circleArray;
}

public static void printCircleArray(Circle3[] circleArray) {
System.out.printf("%-30s%-15s\n", "Radius", "Area");

for (int i = 0; i < circleArray.length; i++) {
System.out.printf("%-30f%-15f\n", circleArray[i].getRadius(),
circleArray[i].getArea());
}
System.out.println("-------------------------------------------");
System.out.printf("%-30s%-15f\n", "The total areas of circles is",
sum(circleArray)); // s-字符串；f-float型。
}

public static double sum(Circle3[] circleArray) {
double sum = 0;

for (int i = 0; i < circleArray.length; i++)
sum += circleArray[i].getArea();

return sum;
}
}

package chapter8对象和类;

public class TV {
int channel = 1;
int volumeLevel = 1;
boolean on = false;

public TV() {
}

public void turnOn() {
on = true;
}

public void turnOff() {
on = false;
}

public void setChannel(int newChannel) {
if (on && newChannel >= 1 && newChannel <= 120)
channel = newChannel;
}

public void setvolume(int newVolumeLevel) {
if (on && newVolumeLevel >= 1 && newVolumeLevel <= 7)
volumeLevel = newVolumeLevel;
}

public void channelUp() {
if (on && channel < 120)
channel++;
}

public void channelDown() {
if (on && channel > 1)
channel--;
}

public void volumeUp() {
if (on && volumeLevel < 7)
volumeLevel++;
}

public void volumeDown() {
if (on && volumeLevel > 1)
volumeLevel--;
}
}