public class Tax3{
    public static void main(String[] args){
        Income[] incomes = new Income[]{new Gongzi(8000),new Gaofei(1000)};        
        getTotal(incomes);    
    }

    public static void getTotal(Income...incomes){
        double tmp = 0.0;        
        for(Income income:incomes){
            tmp += income.total();        
        }
        System.out.println(tmp);    
    }
}

interface Income{
    double money();    
    default double total(){
        return money();    
    }
}

/**
 * 计算工资收入 
*/
class Gongzi implements Income{
    private double income;    
    /**     
      * 赋值    
     * @param money     
    */    
    public Gongzi(double money){
        this.income = money;    
    }

    /**     
      * 计算    
      * @return     
    */    
    public double money(){
        if (income <= 5000) {
            return 0;        
        }
        return (income - 5000) * 0.2;    
    }
}

/** 
* 计算稿费收入 
*/
class Gaofei implements Income{
    private double income;    
    /**     
    * 赋值     
    * @param money     
    */    
    public Gaofei(double money){
        this.income = money;    
    }

    /**     
    * 计算     
    * @return     
    */    
    public double money(){
        if(income < 4000){
            return (income - 800) * 0.7 * 0.2;        
        }
        return income * (1 - 0.2) * 0.7 *0.2;    
    }
}