阅读以下程序，说明Company类和Employee类是 关系。public class Company{ private Employee employee; public Employee getEmployee(){ return employee; } public void setEmployee(Employee employee){ this.employee=employee; } //公司运作 public void run(){ employee.startWorking(); } }
举一反三
- 有如下类的定义，创建Employee对象正确的是（） public class Employee{ private int age; private String name; public void Employee(){ } public Employee(int age){ this.age = age; } public Employee(String name){ this.name = name; } } A: Employee e = new Employee( ) B: Employee e = new Employee(10); C: Employee e = new Employee(tom); D: Employee e = new Employee(10,"tom");
- 有如下类的定义，创建Employee对象错误的是（） public class Employee{ private int age; private String name; public Employee(int age){ this.age = age; } public Employee(String name){ this.name = name; } public Employee(int age,String name){ this(age); this.name = name; } } A: Employee emp = new Employee(10); B: Employee emp = new Employee("Tom"); C: Employee emp = new Employee(); D: Employee emp = new Employee(10,"Tom");
- 下面哪个程序变量age的定义是正确的（） A: public class Employee{ public void show(){ System.out.println(age); } public int age; } B: public class Employee{ public void show(){ System.out.println(age); int age = 20; } } C: public class Employee{ public void show(){ System.out.println(age); } }
- 关于Employee类的对象说法错误的是（） public class Employee{ private int age; private String name; public Employee(){ } public Employee(int age,String name){ this.age = age; this.name = name; } } public class TestEmployee{ public static void main(String[] args){ Employee e1 = new Employee(); Employee e2 = new Employee(10,"tom"); Employee e3 = e2; Employee e4 = new Employee(10,"tom"); } } A: e1对象的name和age属性的值是默认值null和0 B: e2和e3指向相同的内存空间，即指向同一个对象 C: e3和e4对象的age属性值都是10，name属性值都是"tom"，所以是同一个对象 D: 表达式e2==e3的值为true，e3==e4的值为false
- import java.io.*; class Person{ public void print(){System.out.print("Person ");} public void printMyGender(String s){ this.print(); System.out.print(s+" "); } } class Gender{ String type="gender"; public void print(Person p){p.printMyGender(type);} } class Female extends Gender{ public Female(){ type="female"; } } class Male extends Gender{ public Male(){ type="male"; } } class Employee extends Person{ public void print(){ System.out.print("Employee ");} } class Manager extends Employee{ public void print(){ System.out.print("Manager ");} } public class Test{ public static void main(String[] args){ Manager man = new Manager(); Employee em = new Employee(); Gender gender1 = new Male(); Gender gender2 = new Female(); gender1.print(man); gender2.print(em); } } 对于以上代码，其运行结果是