java返回值显示为0.0。为什么会这样？

Question

public   class    employee {

 String empname; 
    int  empcode    ; 
   double basicpay;

    employee()
    {
        empname     =  "";
        empcode     =  0;
        basicpay     =  0.0;
    }
    employee(String n , int p , double q)
    {
        n = empname;
        p = empcode;
        q = basicpay;
    }
    double salarycal()
    {
        double salary,hra,da,allowance,totalsalary;allowance = 0;totalsalary = 0;
        hra = 0.3*basicpay;
        da = 0.4*basicpay;
        salary = basicpay + hra + da;
        if(empcode<=15 && salary<=15000)
        {
            allowance = 0.2*salary;
            if (allowance> 2500)

            allowance  =  allowance - (allowance-2500);
        }
        else 
        {
            allowance = 1000;
         }
        totalsalary =salary + allowance;

        return totalsalary;//the problem is that the total salary is not returned.
    }
}

请说明必须对程序进行哪些更正

Answer 1

它工作正常，因为你用0乘以所有东西

hra = 0.3*basicpay; // basicpay is 0. so 0.
da = 0.4*basicpay; // basicpay is 0. so 0.
salary = basicpay + hra + da; // 0+0+0 = 0

给basicpay分配一个非零值。在构造函数中，您已经交换了参数和字段。如果你使用this这个错误会很明显，比如

employee(String n , int p , double q)
  // n = empname;
  // p = empcode;
  // q = basicpay;
  this.empname = n;
  this.empcode = p;
  this.basicpay = q;
}

此外，类名（按照惯例）应该以大写字母开头Employee

Answer 2

默认构造函数 在默认构造函数中，初始化为零，basicpay = 0.0，然后将所有内容乘以它，所以答案为零

参数化构造函数在参数化构造函数中，赋值错误

 employee(String n , int p , double q)
    {
        n = empname;
        p = empcode;
        q = basicpay;
    }

basicpay是double，即默认值是0.0，所以它也会给你零结果

修改代码：

employee(String n , int p , double q) {
    this.empname = n;
    this.empcode = p;
    this.basicpay = q;
}

Answer 3

我相信你们的一个构装师正在做反向作业。它应该看起来像：

employee(String n , int p , double q)
{
    empname = n;
    empcode = p;
    basicpay = q;
}