出了点错，待改正

package home_work_4_17;


abstract class Employee{
    abstract double  earnings();
}

class YearWorker extends Employee{
     double earnings(){
         System.out.println("按年领取1000");
         return 1000;
     }
}

class MonthWorker extends Employee{
     double earnings(){
         System.out.println("按月领取100");
         return 100;
     }
}

class WeekWorker extends Employee{
     double earnings(){
         System.out.println("按星期领取10");
         return 10;
     }
}

class Company{
    int n;    //该公司的人数
    public Company(int n) {
        this.n=n;// TODO Auto-generated constructor stub
    }
    Employee E[]=new Employee[n];
    
    double cal(){        //返回薪水综合
        double sum=0;
        for(int j=0;j<n;j++){
            sum+=E[j].earnings();
        }
        return sum;
    }
}
public class work_2 {
    public static void main(String args[]) {
        Company c=new Company(3);
        
        c.E[0]=new WeekWorker();
        c.E[1]=new MonthWorker();
        c.E[2]=new YearWorker();
        
        System.out.println("总支出："+c.cal());
    }
}