JAVA实验三(河北工业大学).docx

实验三 面向对象程序设计计C104 李云霄一、类的定义及使用修饰符 class 类名 extends 父类名 implements 接口列表 / 类体 说明： 1）类修饰符分类： 访问修饰符:缺省(默认方式)、public；非访问修饰符：abstract、final ，不能同时修饰一个类 2） extends : 实现继承3） implements : 实现接口class Rectangle1 private int width; private int length; Rectangle1( int i ,int j ) length=30;width=20; void Rectangle(int l,int w) length=l;width=w; Rectangle1(Rectangle1 r) width=r.getWidth(); length=r.getLength();int getWidth() return width; int getLength() return length; class CRctngle public static void main(String args) Rectangle1 x1=new Rectangle1(0,0); Rectangle1 x2=new Rectangle1(50,40); Rectangle1 x3=new Rectangle1(x1); System.out.println(x1.getLength(); System.out.println(x1.getWidth(); System.out.println(x2.getLength(); System.out.println(x2.getWidth(); System.out.println(x3.getLength(); System.out.println(x3.getWidth();2、程序功能：通过两个类StaticDemo、TestDemo说明静态变量/方法与实例变量/方法的区别，程序源代码如下。class StaticDemo static int x; int y; public static int getX() return x; public static void setX(int newX) x=newX;public int getY() return y;public void setY(int newY) y=newY;public class TestDemo public static void main(String args)System.out.println(静态变量x=+StaticDemo.getX();System.out.println(实例变量y=+new StaticDemo().getY(); StaticDemo a=new StaticDemo(); StaticDemo b=new StaticDemo(); a.setX(1); a.setY(2); b.setX(3); b.setY(4); System.out.println(静态变量a.x=+a.getX(); System.out.println(实例变量a.y=+a.getY(); System.out.println(静态变量b.x=+b.getX(); System.out.println(实例变量b.y=+b.getY();二、继承和多态的作用1、编译并运行下面的程序，观察分析运行结果，体会程序中super和this的用法，进一步理解变量隐藏和方法重写的概念。class SuperClss int x; SuperClss() x=10; void doClss() System.out.println(SuperClss.do Class(); class SubClss extends SuperClss int x; SubClss() super(); x=100; void doClss() System.out.println(subClss.doClss();void doDemo() int x; x=1000; super.doClss(); doClss(); System.out.println(super.x=+super.x); System.out.println(this.x=+this.x); System.out.println(x=+x); public class SuperDemo public static void main (String args) SubClss s=new SubClss(); s.doDemo();2、编译并运行下面的程序，分析运行结果，体会其中方法重载的用法，进一步理解方法重载的概念。 class Father void speak() System.out.println(I am Father!); void speak(String s) System.out.println(I like+s+.);public class OverLoadingDemo public static void main(String args) Father x=new Father(); x.speak(); x.speak(music); 三、接口的定义和使用1、接口的实现public class InterfaceTest public static void main(String args) double x; Circle y=new Circle(2.0); x=y.calculate_area(); System.out.println(nthe area is:+x+n); interface Cal_area double PI=3.14; double calculate_area();class Circle implements Cal_area double r; Circle(double r) this.r=r; public double calculate_area() return PI*r*r; 2、 包的定义和使用（1）在包中创建类import java.util.Calendar;/引用 java.util 包public class SY5_1_YMD private int year,month,day;public static void main(String arg3)public SY5_1_YMD(int y,int m,int d) year = y;month = (m=1) & (m=1) & (d=31) ? d : 1);public SY5_1_YMD() this(0,0,0);public static int thisyear() return Calendar.getInstance().get(Calendar.YEAR);/返回当年的年份public int year() return year;/返回年份public String toString()return year+-+month+-+day;/返回转化为字符串的年-月-日（2）编写使用包Mypackage中Test_YMD类的程序 import Mypackage.SY5_1_YMD; /引用Mypackage包中的SY5_1_YMD类public class SY5_2private String name;private SY5_1_YMD birth;public static void main(String args)SY5_2 a= new SY5_2(李云霄,1991,1,1);a.output();public SY5_2(String n1,SY5_1_YMD d1)name = n1;birth = d1;public SY5_2(String n1,int y,int m,int d)this(n1,new SY5_1_YMD(y,m,d);/初始化变量与对象public int age()/计算年龄return SY5_1_YMD.thisyear() - birth.year(); /返回当前年与出生年的差即年龄public void output()System.out.println(姓名: +name);System.out.println(出生日期: +birth.toString();System.out.println(今年年龄: +age();编程题，编写程序并写出运行结果1、创建一个桌子Table类，该类中有桌子名称、重量、桌面宽度、长度及桌子高度属性。其中有：（1）构造函数初始化所有数据成员；（2）Area() :计算桌面的面积；（3）Display(): 在屏幕上输出所有数据成员的值；（4）ChangeWeight(int ):改变桌子重量的函数；（5）在main()中实现创建一个桌子对象，计算桌面的面积，改变桌子重量，并在屏幕上输出所有桌子数据成员的值。package com.kaylves;public class Table private String tableName;/名称 private int weight; /重量 private int length;/长度 private int height;/高度 private int width; /宽度 public Table() tableName=;public Table(String tableName,int weight,int length,int height,int width)this.tableName=tableName; this.weight=weight; this.length=length; this.height=height; this.width=width;public int getArea() return length*width;public void display() System.out.println(桌名称:+this.tableName);System.out.println(重量:+this.weight);System.out.println(长度:+this.length);System.out.println(高度:+this.height); System.out.println(宽度:+this.width); System.out.println(面积:+this.getArea();public void changeWeight(int w)this.weight=w;public static void main(String args) Table table = new Table(小桌子,20,50,20,20); int area=table.getArea(); table.changeWeight(30); table.display();2、创建一个名称为Pay的类，该类包括工作小时、每小时工资、扣缴率、应得工资总额和实付工资等5个双精度型的成员变量。创建3个重载的应得工资computeNetPay()方法。应得工资是工时乘以每小时工资的计算结果。当computeNetPay()接收代表小时、扣缴率和工资率的数值时，计算出应得工资=工作小时*每小时工资*（1扣缴率）*（1工资率）。当computeNetPay()接收两个参数时，扣缴率假定为15%，计算出应得工资=工作小时*每小时工资*（10.15）*（1工资率）当computeNetPay()接收一个参数时，扣缴率假定为15%，每小时工资率为4.65%。同时编写一个测试类，该测试类的main方法测试所有3个重载的方法。public class Pay double work_hour,price=100,deduct_rate;double should_pay,real_pay=0;public double computeNetPay(double work_hour) should_pay=work_hour*this.price*(1-0.15)*(1-0.0465); return should_pay;public double computeNetPay(double work_hour,double price_rate,double deduct_rate) should_pay=work_hour*this.price*(1-deduct_rate)*(1-price_rate); return should_pay;public void display() System.out.println(The employee should be pay $+should_pay);public static void main(String args) Pay pay=new Pay(); System.out.println(The first employee worked 8hour); puteNetPay(8.0); pay.display(); System.out.println(The first employee worked 8hour and price_rate 10% and deduct_rate is 18%); puteNetPay(8.0,0.1,0.18); pay.display();3、商店销售某一件商品，商店每天公布统一的折扣（discount）。同时允许销售人员在销售时灵活掌握价格（price），在统一折扣的基础上，对一次购入10件以上者，还可以销售9.5折优惠。现已知当天5名售货员的销售情况为：售货员编号（num） 销售件数（quantity） 销售单价（price）101 3 126.8221 8 125.6325 10 124.8108 45 123.4901 100 121.5package sale;/我把售货员当作一个个类来继承。 class sale String num; int quantity; double price; public sale(String num, int quantity, double price) this.num=num;this.quantity=quantity;this.price=price;public double amount() return quantity*price; class one extends salepublic one(String num,int quantity,double price) super(num, quantity, price);public double amount() return super.amount();class two extends salepublic two(String num,int quantity,double price)super(num,quantity,price);public double amount() return super.amount();class three extends salepublic three(String num,int quantity,double price)super(num,quantity,price);public double amount() return super.amount();class four extends salepublic four(String num,int quantity,double price)super(num,quantity,price);public double amount() return super.amount();class five extends salepublic five(String num,int quantity,double price)super(num,quantity,price);public double amount() return super.amount();public class testpublic static void main(String args)System.out.println(*商品销售情况*);one one=new one(101, 3, 126.8);one.amount();two two=new two(221, 8, 125.6);two.amount();three three=new three(325, 10, 124.8*0.95);three.amount();four four=new four(108, 45, 124.3*0.95);four.amount(); five five=new five(901, 100, 121.5*0.95);five.amount();double mm=one.price*one.quantity+two.price*two.quantity+three.price*three.quantity+four.price*four.quantity+five.price*five.quantity; System.out.println(当天该商品的销售总额是： +mm); double nn=(one.price*one.quantity+two.price*two.quantity+three.price*three.quantity+four.price*four.quantity+five.price*five.quantity)/(one.quantity+two.quantity+three.quantity+four.quantity+five.quantity); System.out.println(当天该商品的平均售价是： +nn);编写销售商品类Sale和含有main方法的公共类Test，计算当天此商品的总销售额sum，以及每件商品的平均售价，并在显示器上显示。（3）定义接口Shape及其抽象方法getArea()和getPerimeter()用于计算图形和面积和周长。定义类Rectangle(矩形)、类Circle(圆形)、类Triangle(三角形)，要求这些类继承点类Coordinates()并实现接口的抽象方法。package jiekou2; interface shape public double getarea();public double getperimter(); class coordinates double x; double y;public coordinates(double x,double y)this.x=x;this.y=y;class rectangle extends coordinates implements shapepublic rectangle(double x,double y)super(x, y);Overridepublic double getarea() return x*y; Overridepublic double getperimter() return x+x+y+y;class circle extends coordinates implements shapedouble pi= 3.14; public circle(double x,double y) super(x,y); Overridepublic double getarea() return pi*x*x;Overridepublic double getperimter() return 2*pi*x;class triangle extends coordinates implements shape publi