【单选题】父类Person有子类Chinese和American,且两个子类都重写了父类中的walk()方法;下列哪项实现了多态编程 A. Chinese c=new Chinese("张三"); American a=new American("John"); B. Chinese c=new Chinese( "张三"); American a=new American("John"); c.walk(); a.walk(); C. Person person1=new Chinese("张三" ); Person person2=new American("John"); D. Person person1=new Chinese("张三" ); Person person2=new American("John"); person1.walk(); person2.walk();

以下程序片断是否正确？ #include "iostream.h" class Person { private: int m_nAge;[br][/br] public:[br][/br] int GetAge();[br][/br] };[br][/br] int Person:: GetAge() { return m_nAge; } void main()[br][/br] { Person person1; person1.m_nAge=10; cout<<person1.GetAge(); }

class Person { String name; int age; [br][/br] public Person(String name, int age) { super(); this.name = name; this.age = age; } @Override public boolean equals(Object obj) { Person person=null; if(obj instanceof Person) person=(Person)obj; if(name.equals(person.name)&&age==person.age) return true; return false; } } class Test{ public static void main(String&#91;&#93; args) { Person person1 = new Person("张三", 12); Person person2 = new Person("张三", 12); System.out.println(person1.equals(person2));//运行结果是？ } } 程序运行结果是什么？ A: true B: false

新建一个Person类:在类中添加name(姓名),sex(性别),age(年龄),三个私有属性。(2)在Person类中添加一个构造函数,用于给三个属性赋初始值。(3)在Person类中添加__set()方法,用于设置私有属性的值。(4)在Person类中添加__get()方法,用于在类的外部获取私有属性的值。(5)在Person类中添加Display()方法,用于显示所有信息。实例化一个Person对象person1,重新设置性别与年龄,查看修改的性别与年龄的值。调用Display()方法输出person1对象的所有信息。

下列表达式中正确的是()。 A: struct person{<br/>int age; <br/>char<br/>name[8];<br/>char sex;<br/>}personl,person2; B: struct person{<br/>int <br/>age;<br/>char<br/>name[8]; <br/>char sex;<br/>} person<br/>personl,person2; C: struct person{<br/>int <br/>age;<br/>char<br/>name[8];<br/>char sex;<br/>};personl,person2; D: struct person{<br/>int <br/>age;<br/>chat<br/>name[8]="WangLin";<br/>char<br/>sex="M";<br/>} person1

1. The person in dialogue 1 wants to go to the _______________.2. The person in dialogue 2 wants to go to the ______.3. The person in dialogue 3 wants to go to the ______________________.

1. The person in dialogue 1 wants to go to the _______________.

（6-2）定义如下Person类，(1)处合理的代码是。 class Person { String name, department; int age; public Person(String n) { name = n; } public Person(String n, int a) { name = n; age = a; } public Person(String n, int a, String d) { ① department = d; } }

12. There are _________ （1 word）ages in a person’s existence according to Shakespeare.

1、With an older person you generally shake hands and smile, of course.