/////main类

public class Main {

public static double TotalTax(Income... incomes){
double total=0;
for(Income income:incomes){
total+=income.tax();
}
return total;
}

public static void main(String[] args) {
// TODO: 用抽象类给一个有工资收入和稿费收入的小伙伴算税:

//把原来的Income改成了basicIncome。
Income[] incomes = new Income[] { new BasicIncome(3000), new SalaryIncome(7500), new RoyaltyIncome(12000) };
// TODO:
System.out.println(TotalTax(incomes));
}
}

//父类，抽象类

public abstract class Income {
protected double income; public Income(double income){ this.income=income; } public abstract double tax();}z

//子类 BasicIncome

public class BasicIncome extends Income {
public BasicIncome(double income){
super(income);
}
public double tax(){
return income*0.1;
}
}

//子类SalaryIncome

public class SalaryIncome extends Income{

public SalaryIncome(double income){
super(income);
}

public double tax(){
if(income<=5000){
return 0;
}
return (income-5000)*0.2;
}
}

//子类RoyaltyIncome

public class RoyaltyIncome extends Income{
public RoyaltyIncome(double income){
super(income);
}

public double tax(){
return 0;
}
}