Complex c2=new Complex(5,2); Complex c3=new Complex();
System.out.println(c3.add(c1,c2)); System.out.println(c3.jian(c1,c2)); System.out.println(c3.bijiao(c1,c2));} }
（3）public class Calculate { double i,j, t;
public Calculate(int i,int j) {this.i=i; this.j=j;}
public Calculate(int i,int j,int t) {this.i=i;
this.j=j;this.t=t;} public double add() {return i+j;} public double jian() {return i-j;}
public double cheng() {return i*j;} public double chu()
{return i/j;} public double tiji()
{return i*i*i+j*j*j+t*t*t;} }
public class PackageDemo {//测试
public static void main(String[] args) { Calculate c1=new Calculate(8,4); Calculate c2=new Calculate(8,4,2);
System.out.println(\相加=\ System.out.println(\相减=\ System.out.println(\相乘=\ System.out.println(\相除 =\
System.out.println(\立方体体积=\ }
（4）public class BankAccount {
double balance,interest,cunkuan;
public BankAccount(double cunkuan,double balance)//写方法 {this.balance=balance; this.cunkuan=cunkuan;} public void set(double cunkuan)
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{if(cunkuan<10000) interest=0.1;
else if(cunkuan<50000) interest=0.25; else if(cunkuan<100000) interest=0.035; else interest=0.5; }
public double get() { return interest;}
public void chaxun(double balance,double cunkuan) {System.out.println(\存款为：\ System.out.println(\余额为：\ public void qu(double qukuan)
{System.out.println(\取款为：\ System.out.println(\得到的利润率：\ }
public class UseAccount {//测试
public static void main(String[] args) {
BankAccount c1=new BankAccount(40000,40000); c1.chaxun(40000,20000); c1.set(20000);
System.out.println(\利率为\ c1.qu(10000);} }
（5）public class Student { String name; int age;
float average,chainese; float math,Enghish;
public Student(String name,int age) {this.name=name;this.age=age;
System.out.println(name+\岁\ public void set(float chinese,float math,float Enghish) {average= (chinese+math+Enghish)/3;} public float get()
{return average;} }
class Undergraduate extends Student// Student继承Undergraduate {public Undergraduate(String name,int age){ super(name,age); }
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public void hege(float average){ this.average=average; if(average>=60)
System.out.println(\本科生成绩合格\
else System.out.println(\本科生成绩不合格\
class Graduate extends Student// Student继承Graduate {public Graduate(String name,int age){ super(name,age);//调用 }
public void hege(float average){ this.average=average; if(average>=80)
System.out.println(\研究生生成绩合格\
else System.out.println(\研究生成绩不合格\ }
public class StudentDemo {//测试
public static void main(String[] args) {
Undergraduate c1=new Undergraduate(\小明 \ System.out.println(\本科生三门成绩分别为：\ c1.set(65,75,60);
System.out.println(\本科生平均分=\ c1.hege(c1.get());
System.out.println();
Graduate c2=new Graduate(\小红 \
System.out.println(\研究生生三门成绩分别为\
c2.set(80,86,79);
System.out.println(\研究生生平均分=\ c2.hege(c2.get()); }
(6) public abstract class ClosedFigure {//定义抽象类 String shape;
public ClosedFigure(String newShape) {this.shape=newShape;}
public abstract double perimeter();//定义抽象类，里面不能写方法 public abstract double area(); }
public class Triangle extends ClosedFigure {// ClosedFigure继承Triangle double a,b,c;
public Triangle(String newShape,double a,double b,double c) {super(\ this.a=a; this.b=b;
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this.c=c;}
public double perimeter() {return a+b+c;} public double area() {double s;
s=(a+b+c)/2;
return Math.sqrt(s*(s-a)*(s-b)*(s-c));} public String toString()
{return (\三角形三边长：\周长：\面积:\public class Test {
public static void main(String[] args) {
Triangle c1=new Triangle(\三角形\ c1.perimeter(); c1.area();
System.out.println(c1.toString());} } }
（7）public abstract class Employee { private String firstName; private String lastName;
public Employee(String first,String last) {firstName=first;
lastName=last; } public String getEmployeeName() {return firstName;} public String getLastName() { return lastName;} public String toString()
{return firstName+lastName;} public abstract String earnings(); }
public final class Boss extends Employee{ double salary;
public Boss(String first, String last, double salary) { super(first, last); this.salary = salary;} public String earnings() {return (salary+\ }
public final class CommissionWorker extends Employee { double salary;
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double sale; double price;
public CommissionWorker(String first, String last, double salary, double sale,double price) { super(first, last); this.salary = salary; this.sale = sale; this.price = price; }
public String earnings()
{return (salary+sale*price+\ }
public final class PieceWorker extends Employee{ double number; double price;
public PieceWorker(String first, String last, double number,double price) {
super(first, last); this.number = number; this.price=price; }
public String earnings()
{return (number*price+\
}
public final class HourlyWorker extends Employee {double time; double money; public HourlyWorker(String first, String last, double time, double money) {
super(first, last); this.time = time; this.money = money; }
public String earnings() { return (time*money+\}
public class Test {
public static void main(String[] args) { Employee c1=new Boss(\张\三\
System.out.println(\张三月工资：\ Employee c2=new CommissionWorker(\李\四\ System.out.println(\李四月工资：\
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