public String toString() {
return \ } }
11、使用Windows写字板编辑编辑类Cylinder源程序如下： class Cylinder extends Circle {
private double length;
// Default constructor public Cylinder() {
super(); length = 1.0; }
// Construct a cylinder with specified radius, and length public Cylinder(double r, double l) {
super(r); length = l; }
// Getter method for length public double getLength() {
return length; }
// Setter method for length
public void setLength(double length) {
this.length = length; }
// Find cylinder surface area public double findArea() {
return 2*super.findArea()+(2*getRadius()*Math.PI)*length; }
// Find cylinder volume
public double findVolume() {
return super.findArea()*length; }
public boolean equals(Cylinder cylinder) {
return (this.radius == cylinder.getRadius()) && (this.length == cylinder.getLength()); }
// Override the toString() method defined in the Object class public String toString() {
return \ } }
12、使用Windows写字板编辑编辑类Max源程序如下： public class Max {
// Return the maximum between two objects
public static Comparable max(Comparable o1, Comparable o2) {
if (o1.compareTo(o2) > 0) return o1; else
return o2; } }
13、将上面编辑的源程序保存成Java源程序文件(扩展名为java)，程序文件
名分别为TestInterface .java、Circle.java、Cylinder.java、Max.java。 a) 进入命令提示符状态，在源程序文件存放目录下分别编译以上源程
序文件。观察编译后源程序文件存放目录中的文件，熟悉Java程序的文件结构。
b) 如果编译正确，则键入如下命令行，使用Java解释器运行源程序： java TestInterface 程序运行结果如下：
14、使用Windows写字板编辑编辑类Circle，源代码如下： public class Circle {
protected double radius;
public Circle() {
this(1.0); }
public Circle(double radius) {
this.radius = radius; }
public double getRadius() {
return radius; }
public void setRadius(double radius) {
this.radius = radius; }
public double findArea() {
return radius*radius*Math.PI;
}
public double findPerimeter() {
return 2*radius*Math.PI; }
public boolean equals(Circle circle) {
return this.radius == circle.getRadius(); }
public String toString() {
return \ } }
15、使用Windows写字板编辑编辑类TestCloneable，源代码如下： public class TestCloneable {
// Main method
public static void main(String[] args) {
// Declare and create an instance of CloneableCircle CloneableCircle c1 = new CloneableCircle(5); CloneableCircle c2 = (CloneableCircle)c1.clone();
System.out.println(\
// Check if two variables point to the same object if (c1 == c2)
System.out.println(\ else
System.out.println(\
// Check if two objects are of identical contents if (c1.equals(c2))
System.out.println(\ else
System.out.println(\
// Modify c1's radius, name c1.setRadius(10);
c1.getCreator().setFirstname(\ c1.getCreator().setMi(\
// Display c1 and c2
System.out.println(\ System.out.println(\ System.out.println(\
System.out.println();
if (c1 instanceof Cloneable) {
System.out.println(\ } else {
System.out.println(\ }
// Check if a Circle object is cloneable Circle c = new Circle(); if (c instanceof Cloneable) {
System.out.println(\ } else {
System.out.println(\ } } }
// CloneableCircle is a subclass of Circle, which implements the // Cloneable interface
class CloneableCircle extends Circle implements Cloneable {
// Store the creator of the object
private Name creator = new Name(\
// Construct a CloneableCircle with specified radius public CloneableCircle(double radius) {
super(radius); }
// Getter method for creator public Name getCreator()