以Person作为父类，创建学生子类Student,请完善程序。Class Person{ private String name;

1.【填空题】阅读下面的程序,写出程序的运行结果: //filename:App8_2.java 调用父类中的特定构造方法 class Person { private String name; private int age; public Person() { System.out.println("调用了Person类的无参构造方法"); } public Person(String name, int age) { System.out.println("调用了Person类的有参构造方法"); this.name=name; this.age=age; } public void show() { System.out.println("姓名:" name " 年龄:" age); } } class Student extends Person { private String department; public Student() { System.out.println("调用了学生类的无参构造方法Student()"); } public Student (Strin

2.下列程序的运行结果是（） class Student { public Student( ) { System.out.println("无参的构造方法"); } public Student(String name) { System.out.println("一个参数的构造方法"); } public Student(String name, int age) { System.out.println("两个参数的构造方法"); } } public class Example03 { public static void main(String[ ] args) { Student s1 = new Student(); Student s2 = new Student("Rose", 23); Student s3 =new Student("Rose"); } }

3. 创建Person类对象的语句正确的是 public class Person{ private int age; private String name; publicint getAge(){ return age; } public String getName(){ return name; } public void setAge(int age){ this.age = age; } public void setName(String name){ this.name = name; } public void show(){ System.out.println("姓名:"+name+",age"+age); } } 选项： A、 Person p = new Person; B、 Person p = Person(); C、 Person = new Person(); D、 Person p = new Person();

4. 以下说法正确的是 public class Person{ private int age; private String name; publicint getAge(){ return age; } public String getName(){ return name; } public void setAge(int age){ this.age = age; } public void setName(String name){ this.name = name; } public void show(){ System.out.println("姓名:"+name+",age"+age); } } public class TestPerson{ public static void main(String[] args){ Person p = new Person(); } } 选项： A、 p能调用的方法有setAge(int),getAge(),setName(String),setAge(int) B、 p是Person类的对象 C、 p能调用的方法有Person() D、 p.setName("Tom")能把p的姓名属性赋值为Tom

5.//定义人员类 class Person { private String name;//姓名 private int age;//性别 private String address;//住址 public Person(){} public Person(String name,int age) { this.name=name; this.age=age; } public Person(String name,int age,String address) { ( ① )//调用本类的构造方法 this.address=address; } //省略setter和getter }

6.class Student{String name;public void show(){System.out.println("姓名："+name);}}下面定义Student类的构造方法正确的是（）。选项： A、public void Student(){name = "张三";} B、public Student(){name = "张三";} C、public void Student(String myName){name = myName;} D、public Student(String myName){name = myName;}

7.下面程序显示结果。public class Test{ public static void main(String [] args){ Student zhangsan = new Student("张三", 19, 87); Student lisi = zhangsan; lisi.display(); }}public class Student{ private String name; private int age; private double grade; public Student(String name, int age, double grade){ this.name = name; this.age = age; this.grade = grade; } public void display(){ System.out.println("姓名：" + name); }}选项： A:姓名： B:姓名：null C:姓名：张三 D:姓名：李四

8.What is the output of the following code? ( )Public class Test {Public static void main(String] args) {New Person().printPerson();New Student().printPerson();}}Class Student extends Person {Private String getInfo() {Return "Student";}}Class Person {Private String getInfo() {Return "Person";}Public void printPerson() {System.out.println(getInfo());} } 选项： A:Person Person B:Person Student C:Stduent Student D:Student Person

9.定义一个新的类Student，继承Person类，要求：(1)增加 String 类型的属性“school”；(2)编写 Student 类的构造方法 Student(String name, int age, String school)，并调用父类构造方法；(3)重写Person 类的 info()方法。

10.下列代码的输出是什么public class Test { public static void main(String[] args) { new Person().printPerson(); new Student().printPerson(); }} class Student extends Person { private String getInfo() { return "Student"; }} class Person { private String getInfo() { return "Person"; } public void printPerson() { System.out.println(getInfo()); }}选项： A:Person Person; B:Person Student; C:Stduent Student; D:Student Person

11. 单选题What is the output of the following code? ( )Public class Test {Public static void main(String] args) {New Person().printPerson();New Student().printPerson();}}Class Student extends Person {Private String getInfo() {Return "Student";}}Class Person {Private String getInfo() {Return "Person";}Public void printPerson() {System.out.println(getInfo());}} 选项： A:Person Person B:Person Student C:Stduent Student D:Student Person

12.有类Person的定义如下，创建对象的语句正确的有（） class Person{ int age; String name; public Person(int age){ this.age = age; } public Person(String name){ this.name = name; } public void Person(int age, String name){ this.age = age; this.name = name; } } 选项： A、Person p = new Person（）; B、Person p = new Person(10); C、Person p = new Person( "tom"); D、Person p = new Person( 10, "tom");

13.给出程序的运行结果（） class Person { String name; int age; Person(){ System.out.println("Person()"); } void Person(){ System.out.println("method()"); } public void tell() { System.out.println("姓名：" + name + "，年龄：" + age); } } public class ClassTest02 { public static void main(String[] args) { Person person = new Person(); person.name = "张三"; person.age = 30; person.tell(); } }

14.class Student{ private String name; public Student(String name) { this.name=name; } public void setName(String name) { this.name=name; } public String getName() { return name; }}public class test4 { public static void modifyStudent(Student std) { std.setName("张三"); } public static void main(String[] args) { Student s1=new Student("李四"); System.out.println(s1.getName()); modifyStudent(s1); System.out.println(s1.getName()); }}

15. 单选题What is the output of the following code? ( )Public class Test {Public static void main(String] args) {New Person().printPerson();New Student().printPerson();}}Class Student extends Person {@OverridePublic String getInfo() {Return "Student";}}Class Person {Public String getInfo() {Return "Person";}Public void printPerson() {System.out.println(getInfo());}} 选项： A:Person Person B:Person Student C:Stduent Student D:Student Person

16.找出下面代码中存在的错误。public class Test { public static void main(String[] args) { m(new GraduateStudent()); m(new Student()); m(new Person()); m(new Object()); } public static void m(Student x) { System.out.println(x.toString()); }}class GraduateStudent extends Student {}class Student extends Person { @Override public String toString() { return "Student"; }}class Person extends Object { @Override public String toString() { return "Person"; }}

17.private String name; public Student(){ name = "Unknown"; } public void setName (String n){ name = n; } public String getName(){ return name; }}class Cl1{ public static void main(String[] args){ Student a = new Student(); System.out.println(a.getName()); a.setName("xyz"); String b = a.getName(); System.out.println(b); }}输出是Unknownxyz选项： A:正确; B:错误

18.阅读下列程序，并给出程序运行的结果。Public class PolymorphismDemo {Public static void main(String] args) { m(new GraduateStudent()); m(new Student()); m(new Person());} Public static void m(Object x) {System.out.println(x.toString());}} Class GraduateStudent extends Student {} Class Student extends Person {Public String toString() { return "I am a student";}} Class Person extends Object {Public String toString() { return "I am a person";}}

19.【填空题】23. import java.text.*; public class Java_2 { public static void main(String[] args) { Person[] people = new Person[2]; people[0] = new Worker("老张", 30000); people[1] = new Student("小王", "计算机科学"); for (int i = 0; i < people.length; i++) { Person p = people[i]; //*********Found********** System.out.println(____________________() + ", " + p.getDescription()); } } } //*********Found********** ________________ class Person { public Person(String n) { name = n; } //*********Found********** public ___________________ String getDescription(); public String getName() { return name; } private String name; } //*********Found********** class Worker _________________ Person { public Worker(String n, double s) { super(n); salary = s; } public String getDescription() { NumberFormat formatter = NumberFormat.getCurrencyInstance(); return "工人，年薪是 " + formatter.format(salary) + "。"; } private double salary; } //*********Found********** class Student _________________ Person { public Student(String n, String m) { super(n); major = m; } public String getDescription() { return "学生，专业是 " + major + "。"; } private String major; }

20.给出程序的运行结果（）class Person { String name; int age; Person(){ System.out.println("Person()"); } void Person(){ System.out.println("method()"); } public void tell() { System.out.println("姓名：" + name + "，年龄：" + age); } }public class ClassTest02 { public static void main(String[] args) { Person person = new Person(); person.name = "张三"; person.age = 30; person.tell(); }}选项： A:Person()姓名：张三，年龄：30 B:姓名：张三，年龄：30 C:Person()method()姓名：张三，年龄：30 D:method()姓名：张三，年龄：30

21.编译运行如下代码，输出结果是（）。Class Person {String name=”person”;public void shout(){System.out.prinnt(name);}}Class Student extends person{String name=”student”;Student school=”school”;}Class Text {public static void main(String [] args){Person p=new Student();p.shout();}} 选项： A、person B、student C、person D、编译错误