实验五-继承与接口

1、实验五 继承与接口1. 实验目的1、掌握类的继承细节内容，包括子类的继承、子类对象创建、成员变量的继承与隐藏、方法的继承与重写2、掌握重写的目的以及怎样使用super 关键字3、掌握上转型对象与接口回调技术4、掌握类怎样实现接口，及面向接口的编程思想2. 实验内容1、根据附录里的源代码，按照注释要求，完成代码填空，使程序能够运行得出结果。1）实验 1 中国人与美国人package boy;public class People protected double weight , height ;public void speakHello()System. out .println( &quo

2、t;yayayaya" ); public void averageHeight() height =173;System. out .println( "average height:" +height );public void averageWeight()weight =70;System. out .println( "average weight:" +weight ); package boy;public class ChinaPeople extends Peoplepublic void speakHello() Syste

3、m. out .println( " 你好 " );public void averageHeight()height =168.78;System. out .println( " 中国人的平均身高:" +height +" 厘米 " );public void averageWeight() weight =65;System. out .println( " 中国人的平均体重:" +weight +" 公斤 " );/【代码1】/重写public void averageWeight()方

4、法，输出："中国人的平均体重：65公斤"public void chinaGongfu()System. out .println( "坐如钟，站如松,睡如弓");package boy;public class AmericanPeople extends Peoplepublic void speakHello() System. out .println( "How do you do" );public void averageHeight() System. out .println( "American'

5、s average height:176cm");/ 【代码 2】/ 重写 public void speakHello()方法，输出："How do you do"/ 【代码 3】/ 重写 public void averageHeight()方法，输出："American's averageheight:176cm"public void averageWeight()weight =75;System. out .println( "American's average weight:"+weight

6、+"kg");public void americanBoxing()System. out .println( "直拳、钩拳、组合拳 ");package boy;public class BeijingPeople extends ChinaPeople public void averageHeight() System. out .println( "北京人的平均身高 :172.5 厘米")； public void averageWeight() System. out .println( "北京人的平均体重 :7

7、0 公斤"); /【代码4】/重写public void averageHeight() 方法，输出:"北京人的平均身高:172.5 厘米" /【代码5】/重写public void averageWeight()方法，输出："北京人的平均体重：70公斤”public void beijingOpera()System. out .println( "花脸、青衣、花旦和老生");package boy;public class Example public static void main(String口 args ) ChinaPe

8、ople chinaPeople = new ChinaPeople(); AmericanPeople americanPeople = new AmericanPeople(); BeijingPeople beijingPeople = new BeijingPeople(); chinaPeople .speakHello();americanPeople .speakHello();beijingPeople .speakHello();chinaPeople .averageHeight(); americanPeople .averageHeight(); beijingPeop

9、le .averageHeight(); chinaPeople .averageWeight(); americanPeople .averageWeight(); beijingPeople .averageWeight(); chinaPeople .chinaGongfu(); americanPeople .americanBoxing(); beijingPeople.beijingOpera();beijingPeople.chinaGongfu();你好How do you do你好中国人的平均身高：168.78 厘米American's average height:

10、176cm 北京人的平均身高：172.5 厘米 中国人的平均体重：65.0 公斤American's average weight:75.0kg 北京人的平均体重：70公斤 坐如钟，站如松，睡如弓 直拳、钩拳、组合拳 花脸、青衣、花旦和老生 坐如钟，站如松，睡如弓2)实验2银行与利息package boy;public class Bank int savedMoney ;int year ;double interest ;public double computerInterest()interest =year * interestRate * savedMoney ; retu

11、rn interest ;public void setInterestRate( double rate ) interestRate = rate ; package boy;public class ConstructionBank extends Bank double year ;public double computerInterest()super . year =( int ) year ;double r =year -( int ) year ; int day =( int )( r *1000);double yearInterest =super .computer

12、Interest(); / 【代码 1 】 /super 调用隐 藏的 computerInterest() 方法double dayInterest =day *0.0001* savedMoney ;interest =yearInterest +dayInterest ;System. out .printf( "%d元存在建设银行 %d年零d天的利息：f元 n" , savedMoney , super . year , day , interest );return interest ; package boy;public class BankOfDalian

13、extends Bank double year ;public double computerInterest() super . year =( int ) year ; double r =year -( int ) year ; int day =( int )( r *1000);double yearInterest =super .computerInterest(); / 【代码 2】 /super 调用隐 藏的 computerInterest() 方法double dayInterest =day *0.00012* savedMoney ;interest =yearIn

14、terest +dayInterest ;System. out .printf( "%d元存在大连银行 %d年零d天的利息：f元 n" , savedMoney , super . year , day , interest );return interest ;package boy;double interestRate=0.29;public class SaveMoney public static void main(String口args ) int amount =8000;ConstructionBank bank1 =new ConstructionBa

15、nk();bank1 . savedMoney =amount ;bank1 . year =8.236;bank1 .setInterestRate(0.035);double interest1 =bank1 .computerInterest(); BankOfDalian bank2 =new BankOfDalian();bank2 . savedMoney =amount ;bank2 . year =8.236;bank2 .setInterestRate(0.035);double interest2 =bank2 .computerInterest();System. out

16、 .printf( "两个银行利息相差 %f 元坨"，interest2 - interest1 ); 8000元存在建设银行 8年零236天的利息：2428.800000 元8000元存在大连银行 8年零236天的利息：2466.560000 元两个银行利息相差 37.760000 元3)实验3面积之和Geometry.javapublic abstract class Geometry public abstract double getArea();package boy;public class TotalArea Geometry口 tuxing ;double

17、totalArea =0;public void setTuxing(Geometry口t )tuxing =t ;public double computerTatalArea()for (int i =0; i <tuxing . length ; i +) totalArea +=tuxing i .getArea();/【代码3】/用循环语句让tuxing的元素调用getArea 方法，并将返回的值累加到 totalAreareturn totalArea package boy;public class Rect extends Geometry double a, b;Rec

18、t( double a, double b) this . a=a; this . b=b;public double getArea() return a*b;/【代码1】/重写getArea() 方法package boy;public class Circle extends Geometry double r;Circle( double r) this . r=r ;public double getArea() return 3.14* r *r;/【代码2】/重写getArea() 方法 package boy;public class MainClass public stat

19、ic void main(String口 args ) Geometry口tuxing =new Geometry29; / 有 29 个 Geometry 对象for (int i =0; i <tuxing . length ; i +) /29 个 Geometry 对象分成两类if (i %2=0)tuxing i = new Rect(16+ i ,68); else if (i %2=1)tuxing i = new Circle(10+ i); TotalArea computer =new TotalArea();computer .setTuxing( tuxing )

20、;System. out .printf("各种图形的面积之和：n%f" , computer .computerTatalArea();各种图形的面积之和：58778.3600004）实验4 歌手大赛package boy;public interface ComputerAverage public double average( double x ); package boy;public class SongGame implements ComputerAveragepublicdouble average(double x )intcount =x. lengt

21、h ;double aver =0, temp =0;for ( int i =0; i <count ; i +)for ( int j =0; j <count ; j +)if (xj<xi)temp =x j ;x j = x i ;x i = temp ;for ( int i =0; i <count ; i +) aver =aver +x i ;if ( count >2)aver =aver /( count -2); else aver =0; return aver ;package boy;public class School imple

22、ments ComputerAveragepublic double average( double x ) / 【代码 1 】 / 重写 public doubleaverage(double x口)方法，返回数组 x口的元素的算术平方double sum=0;for (int i =0; i <x. length ; i +) sum+=x i ;return sum/x. length ; package boy;public class Estimator public static void main(String口 args ) double a=6.6,3.4,5.7,8.

23、9;double b=5.6,7.5,4.3,2.9;ComputerAverage computer ;computer =new SongGame();double result =computer .average( a); /【代码 2/computer调用 average(x口)方法，将数组a传递给参数xSystem. out .printf( "%n");System. out .printf("歌手最后得分：%5.3fn" , result );computer =new School();result =computer .average

24、( b); /【代码 3】/computer 调用 average(x口)方法,将数组b传递给参数xSystem. out .printf("学生平均体重：%-5.2f kg" , result ); 歌手最后得分：12.300 学生平均体重：5.07 kg5)实验5天气预报package boy;public interface WeatherState public void showState(); / 重写 public void showState() 方法 package boy;public class Weather WeatherState state ;

25、public void show() state .showState();public void setState(WeatherState s)state =s; package boy;public class CloudyLittleState implements WeatherStatepublic void showState()System. out .print( " 少云，有时晴。" ); package boy;public class HeavyRainState implements WeatherStatepublic void showStat

26、e() / 【代码2】 / 重写 public void showState()方法System. out .print( " 暴雨，有闪电。" ); package boy;public class LightRainState implements WeatherStatepublic void showState() / 【代码2】 / 重写 public void showState()方法System. out .print( " 小雨，转多云。" ); package boy;public interface WeatherState pub

27、lic void showState(); / 重写 public void showState() 方法 package boy;public class WeatherForecast public static void main(String args ) Weather weatherBeijing =new Weather();System. out .print("n 今天白天：" );weatherBeijing.setState(new CloudyDayState();weatherBeijing.show();System. out .print(&q

28、uot;n 今天夜间：" );weatherBeijing .setState(newLightRainState();weatherBeijing.show();System. out .print( "n 转：" );weatherBeijing .setState(newHeavyRainState();weatherBeijing.show();System. out .print("n 明天白天：" );weatherBeijing.setState(new LightRainState();weatherBeijing.show()

29、;System. out .print("n 明天夜间：" );weatherBeijing.setState(new CloudyLittleState();weatherBeijing.show();今天白天：少云，有时晴。今天夜间：小雨，转多云。转：暴雨，有闪电。明天白天：小雨，转多云。明天夜间：少云，有时晴。2、设计编写程序完成以下任务。1)根据要求修改实验2，参照建设银行再编写一个商业银行(广发行)，让程序输出8000 元在广发行8 年零 212 天的利息。package boy; public class Bank int savedMoney ; int ye

30、ar ; double interest ; double interestRate =0.29; public double computerInterest() interest =year * interestRate * savedMoney ; return interest ; public void setInterestRate( double rate ) interestRate = rate ; package boy;public class ConstructionBank extends Bank double year ; public double comput

31、erInterest() super . year =( int ) year ; double r =year -( int ) year ; int day =( int )( r *1000);double yearInterest =super .computerInterest(); / 【代码 1 】 /super 调用隐 藏的 computerInterest() 方法double dayinterest =day *0.0001* savedMoney ;interest =yearInterest+dayInterest ;System. out .printf( "

32、;%d元存在建设银行 %d年零d天的利息：f元 n" , savedMoney , super . year , day , interest );return interest ; package boy;public class SaveMoney public static void main(String口args ) int amount =8000;ConstructionBank bankl =new ConstructionBank(); bankl . savedMoney =amount ;bankl . year =8.212;bankl .setInteres

33、tRate(0.035);double interestl =bank1 .computerInterest(); 加。0元存在建设银行&年零zii天的利息：240B.£000002)根据要求修改实验3,再增加一种几何图形(梯形)，并让主类中的tuxing 的某些元素是梯形的上转型对象。package fourl;public abstract class Geometry public abstract double getArea();package fourl;public class TotalArea Geometry口tuxing ;double totalAre

34、a =0;public void setTuxing(Geometry口 t )tuxing =t ;public double computerTatalArea()for (int i =0; i <tuxing . length ; i +) totalArea +=tuxing i .getArea();/【代码3】/用循环语句让tuxing的元素调用getArea 方法，并将返回的值累加到 totalAreareturn totalArea ;package fourl;public class Trapezoid extends Geometrydouble x, y, z;

35、Trapezoid( double x, double y, double z)this . x=x;this . y=y;this . z=z;public double getArea()return z*( x+y)/2;package four1;public class MainClass public static void main(String口 args ) Trapezoid tuxing =new Trapezoid(4.6,4.6,7.9);/ 有 29 个 Geometry 对象double s =tuxing .getArea();System. out .prin

36、tf( "梯形的面积为：n%f" , s);两形的百积为：3)仿照实验5编写一个程序实现模拟水杯中的水在不同温度下可能出现的 状态。package four1;public class BoiledState implements WaterStatepublic void showState() System. out .println( "开水。"); package four1;public class IceState implements WaterStatepublic void showState()System. out .print(

37、"结冰。");package four1;public class LittleWarmState public void showState() System.out.println(implements WaterState"微凉。");package four1;public class WarmState implements WaterState public void showState() System.out.println( "温水。");/ 【代码 2】/ 重写 public void showState() 方法

38、package fourl;public class Water WaterState state ; public void show()state .showState();public void setState(WaterState s) state =s; package four1; public class WaterForecast public static void main(String口 args) Water waterState=new Water();System. out .print( waterState.setState( waterState.show(

39、);System. out .print( waterState.setState( waterState.show();"n"n温度在90-100时水杯水的状态:new BoiledState();温度在50-80 时水杯水的状态:new WarmState();");");System. out .print( waterState.setState( waterState.show(); System. out .print( waterState.setState( waterState.show();"n"n温度在30-50

40、时水杯水的状态:new LittleWarmState();温度在0度下时水杯水的状态: new IceState();")；")；package fourl;public interface WaterState public void showState();实验结果<tern'iinatea> waterrorecasi pava /温度在9。1 口口时水杯中水的状态开水n温度在50-90时水杯中水的状态 温水。温度在30-50时水杯中水的状态:微源*温度在。-30时水杯中水的状志二给冰。4)编写一个接口并创建两个实现该接口的类 A、Bo A B类

41、实现了接口的f 方法，A类的f方法内容为计算1! +3! +5!+9!并返回结果，B类的f方 法内容为计算2! +4! +6! +10!也返回结果；再编一个执行类，执行类运 行时要求通过接口回调方式用同一个对象实例分别调用A类的f方法和B类的f方法。package four1;public class A implements object public int f( int a, int b) int sum=0,temp=1;for (int i=a;i<=b;i=i+2) for (int j=1;j<=i;j+) temp*=j; sum+=temp; temp=1;ret

42、urn sum;package fourl;public class B implements object public int f( int a, int b) int sum=0,temp=1;for (int i=a;i<=b;i=i+2) for (int j=1;j<=i;j+) temp*=j; sum+=temp; temp=1; return sum;package four1;public interface object int f( int a, int b);package four1;public class Test public static voi

43、d main(String口 args) A a= new A();B b= new B();int sum1=a.f(1, 9);+sum1);"+sum2);int sum2=b.f(2, 10);System. out .println("1 ! +3! +5 ! +9 !的结果为：System. out .println("2 ! +4! +6 ! +10!的结果为:实验结果R Javadoc Declaration QConsole x Debug<terminated> Test (1) Java Application CPragranr

44、 Qose avajdk -12.0.2bin111 +3! +5! +9l 的造果为：3690472! +4! +6!的结果为：3669B665)(1)定义一个汽车类Vehicle ,要求如下：(知识点：类的继承 方法的覆盖)(a)属性包括：汽车品牌brand (String类型)、颜色color (String类型) 和速度speed (double类型)。(b)至少提供一个有参的构造方法(要求品牌和颜色可以初始化为任意值， 但速度的初始值必须为0)。(c)为属性提供访问器方法。注意：汽车品牌一旦初始化之后不能修改。(d)定义一个一般方法run(),用打印语句描述汽车奔跑的功能。定义测试类

45、VehicleTest ,在其main方法中创建一个品牌为“ benz”、颜 色为“black”的汽车。(2)定义一个Vehicle类的子类轿车类Car,要求如下：(a)轿车有自己的属性载人数loader (int类型)。(b)提供该类初始化属性的构造方法。(c)重新定义run(),用打印语句描述轿车奔跑的功能。(d)定义测试类Test,在其main方法中创建一个品牌为“ Hondd'、颜色 为“red”，载人数为2人的轿车。面向对象基础出过类似的，这个把继承引入了package four1;public class Car extends Vehicle int loader ;pu

46、blic Car(String brand, String color,double speed, int l) super (brand, color, speed);this . loader =l;public void run()System. out .println( "颜色为"+super .getColor()+ "的"+super .getBrand()+ 汽车的时速为："+super .getSpeed(); package four1;public class Test public static void main(St

47、ring口 args) Car c= new Car( "Honda" , "red" ,300.0,20); c.run();package four1;public class Vehicle privateStringbrand ="BMW" / 汽车品牌privateStringcolor ="red" ; / 汽车颜色privatedoublespeed =0; /汽车时速publicString getColor() return colorpublic void setColor(String col

48、or) this . color = color;public double getSpeed() return speed ;public void setSpeed( double speed) this . speed = speed;public String getBrand() return brand ;public Vehicle(String brand, String color,double speed) this . brand =brand;this . color =color;this . speed =speed;public void run()System.

49、 out .println( brand +"汽车的时速为："+speed );package four1;public class VehicleTest public static void main(String口 args) Vehicle v= | new Vehicle( "benz" , "black" ,200.0); v.run();实验结果<ieroiiiidieo> verncieieE>i JdVd /ppntdLiucij c:rnjyidi b电nz汽车的时速为：200.06) Cola公

50、司的雇员分为以下若干类：(知识点：多态)(1) ColaEmployee :这是所有员工总的父类，属性：员工的姓名，员工的生 日月份。方法：getSalary(int month)根据参数月份来确定工资，如果该月员工过生日，则公司会额外奖励100(2) SalariedEmployee : ColaEmployee 的子类，拿固定工资的员工。属性：月薪(3) HourlyEmployee : ColaEmployee的子类，按小时拿工资的员工，每月 工作超出160小时的部分按照1.5倍工资发放。属性：每小时的工资、每月工作的小时数(4) SalesEmployee : ColaEmployee

51、的子类，销售人员，工资由月销售额 和提成率决定。属性：月销售额、提成率(5)定义一个类Company在该类中写一个方法，调用该方法可以打印出某 月某个员工的工资数额，写一个测试类 TestCompany,在main方法，把若干各种 类型的员工放在一个 ColaEmployee数组里，并单元出数组中每个员工当月的工知识点：继承与多态package four1;public class ColaEmployee String name; / 员工姓名int month; /员工生日月份public String getName() return name;public void setName(S

52、tring name) this .name = name;public int getMonth() return month;public void setMonth( int month) this .month = month;int getSalary( int month) if (month = this .month)return 100;else return 0;package four1;public class Company extends ColaEmployeevoid print(String name,double salary, int month)Stri

53、ng Name=name;double Salary=salary;+Salary);int Month=month;System. out .println( "员工"+Name+"在"+Month+ "月"+"的薪资为:package four1;public class HourlyEmployee extends ColaEmployee double hours; /每月工作的时间double hsalary; /每小时的工资name, int month, double hours, double hsalary

54、)Company c= new Company。；public HourlyEmployee(String this .hours=hours;this .hsalary=hsalary;this .month=month; this .name=name;public double getHours() return hours;public void setHours( double hours) this .hours = hours;public double getHsalary() return hsalary;public void setHsalary( double hsal

55、ary) this .hsalary = hsalary;public int getSalary(int month)if (this .hours<=160)this .hsalary=this .hsalary*this .hours+ super .getSalary(month);c.print(name,hsalary,month);return 0; else this .hsalary=( this .hours-160)* this .hsalary*1.5+160* this .hsalary+ super .g etSalary(month);c.print(name,hsalary,month); return 0;package four1;public class SalariedEmployee extends ColaEmployee double salary; /员工固定薪资(按月)int month, double salary) Company c= new Company。；public SalariedEmployee(String name,this .name=name;t