接口练习

课堂练习1：动物声音模拟器

public interface Animal {void cry();String getAnimalName() ;}

public class Simulator {void playSound(Animal animal) {System.out.println(animal.getAnimalName()+"的叫声：");animal.cry();}}

public class Dog implements Animal{public void cry() {System.out.println("汪汪汪");} public String getAnimalName(){return "旺财";}}

public class Cat implements Animal{public void cry() {System.out.println("喵喵喵");}public String getAnimalName(){    return "咪呜";}}

public class Application {public static void main(String[] args) {Simulator simulator = new Simulator();simulator.playSound(new Dog());simulator.playSound(new Cat());}}

课堂练习2：大学里的学生（Student）需要交学费，而研究生（Graduate）作为学生比较特殊，除了需要交学费外，还可以获取一部分科研津贴，由学校（University）统一发放。此外，学校还需要发放教师（Teacher）的工资。

public abstract class Student {int fee;String name;Student(String name){this.name = name; }void setFee(int fee){this.fee = fee;}abstract int getFee();}

public interface Salary {int getSalary();}

public class Graduate extends Student implements Salary{int salary = 1500;Graduate(String name){super(name);}void setFee(int fee){this.fee = fee;}int getFee(){return fee;}public int getSalary(){System.out.println("研究生的工资："+salary);return salary;}boolean isLoan(){if(salary < fee)return true;return false;}}

public class Teacher implements Salary{int salary = 3000;String name;Teacher(String name){this.name = name;}public int getSalary(){System.out.println("教师的工资："+salary);return salary;}}

public class University {public void payOff(Salary s){s.getSalary();}}

public class Test {public static void main(String[] args) {Graduate g = new Graduate("小亮");g.setFee(1000);University u = new University();u.payOff(g);System.out.println("是否需要贷款："+g.isLoan());Teacher t = new Teacher("大王");u.payOff(t);}}