class Employee; class Manager extends Employee; class Director extends Employee;
举一反三
- 已知：class Employee;class Manager extends Employee;class Director extends Employee;则以下语句能通过编译的有哪些？ A: Employee e = new Manager(); B: Director d = new Manager(); C: Director d = new Employee(); D: Manager m = new Director()
- 已知类的继承关系 class Employee; class Manager extends Employee; class Director extands Employee; class Director extands Employee; 下语句能通过编译的有哪些?
- 已知类的继承关系如下： class Employee; class Manager extends Employee; class Director extends Employee; 则以下语句能通过编译的有哪些？
- 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
- Which two demonstrate an “is a” relationship？ （） A: public interface Person{} public class Employee extends Person{} B: public interface Shape{} public class Employee extends Shape{} C: public interface Color{} public class Employee extends Color{} D: public class Species{} public class Animal （private Species species；） E: interface Component{} Class Container implements Component （ Private Component[ ] children； ）