使用继承时会出现 Java 操作数错误，但在单个类上执行相同操作时不会出现错误

Question

首先，是的，这是家庭作业(但我正在自己做作业)。我一直在努力工作，但我不明白我做错了什么。

该作业要求销售人员的基本工资和佣金分为两类。

我确信您之前已经看过此内容，但我找不到涉及此问题的其他帖子。

我的基本工资等级。

package salescommission;

public class SalesBaseSalary {

    public SalesBaseSalary() {

        int baseSalary = 75000;

    }
}

以及我的销售佣金类别

package salescommission;

//Adding Scanner Utility
import java.util.Scanner;


public class SalesCommission extends SalesBaseSalary {
    public static void main(String[] args) {
        //Scanner input
        Scanner input = new Scanner( System.in );
        int totalSales;
        int salesPlusSalary;

        //input commissions        
        System.out.print( "Enter Annual Commissions" );
        totalSales = input.nextInt();

        salesPlusSalary = (int) (totalSales * .05 + SalesBaseSalary);

        System.out.printf( "Sales commission plus Salary is %d\n", salesPlusSalary );  
    }
}

现在，如果我将其作为一个类来执行，它会完美地工作......但我必须有两个。这是单个类。

package salescompensation;

//Adding Scanner Utility
import java.util.Scanner;

//Main Class representing the employees base salary
public class SalesCompensation {

    public static void main(String[] args) {
        //Scanner input
        Scanner input = new Scanner( System.in );
        int totalSales;
        int salesPlusSalary;
        //base salary    
        double baseSalary = 75000;    
        //input commissions        
        System.out.print( "Enter Annual Commissions" );
        totalSales = input.nextInt();

        salesPlusSalary = (int) (totalSales * .05 + baseSalary);

        System.out.printf( "Sales commission plus Salary is %d\n", salesPlusSalary );

    }

}

我试图找出我做错了什么以及为什么做错了，这样我就可以学习。

Answer 1

要扩展 sheltem 的答案，您应该从 SalesCommission 类的实例获取该字段(假设它不是类常量)。

public static void main(String[] args) 
{
   // Create an instance of the SalesCommission class (an object)
   SalesCommission salesCommission = new SalesCommission();

   //Scanner input
   Scanner input = new Scanner( System.in );
   int totalSales;
   int salesPlusSalary;

   //input commissions        
   System.out.print( "Enter Annual Commissions" );
   totalSales = input.nextInt();

   salesPlusSalary = (int) (totalSales * .05 + SalesCommission.baseSalary);

   System.out.printf( "Sales commission plus Salary is %d\n", salesPlusSalary );  
}

此外，由于您刚刚掌握 Java、OOP 和类等知识，我建议您阅读 The Java Tutorials或其他类似的资源，并审查您的设计以及如何改进它。通过努力提高，您将学习 OOP 和良好的设计/实践。