} }
10、以下程序的输出结果为＿＿＿＿。 class Person {
private String name; public Person() { this(\陈敏\ }
public Person(String setName) { name = setName; }
public String getName() { return name; } }
class Teacher extends Person { private String id;
public Teacher(String s1, String s2) { super(s1);
id = s2; }
public String getId() { return id; } }
public class Test {
public static void main(String[] args) {
Teacher t = new Teacher(\黄牧\ System.out.println(t.getName()); System.out.println(t.getId()); } }
12、以下程序的输出结果为＿＿＿＿＿＿＿＿。 interface Runner {
public abstract void run(); }
class Dog
implements Runner {
public void run() {
System.out.println(\ } }
class Horse
implements Runner { public void run() {
System.out.println(\ } }
public class Test {
public static void run(Runner r) { r.run(); }
public static void main(String[] args) { Runner horse = new Dog(); run(horse); } }
13、编程判断指定的字符串是否是合法的Java标识符？请在空白处填上适当的语句。 public class Identifier {
public static boolean isIdentifier(String str) {
if (str!=null && str.length()>0) {
char ch = str.charAt(0); if ( ) {
for (int i=1; i ch = str.charAt(i); if (!(ch>='A' && ch<='Z' || ch>='a' && ch<='z' || ch=='_' || ch=='$' || ch>='0' && ch<='9')) ____________________________ } _______________________________ } } return false; } public static void main(String args[]) { String str = \ if (args.length>0) str=args[0]; System.out.println(\} 14、可计算面积的接口与实现该接口的矩形类 interface Area //定义可计算面积接口 { _________________________________; //计算面积的抽象方法 } public class Rectangle ________________________ //定义矩形类，实现接口Area { protected double length, width; //长度和宽度