如何访问抽象超类实例变量 [英] How to access Abstract superclass instance variable

问题描述

所以我有两个类:Property 和 Houses.Property 是抽象超类，Houses 是它的子类.

这是Property

的代码

公共抽象类属性{字符串代码；双倍价值；整数年；公共属性(字符串 pCode，双值，整数年){this.pCode = pCode;this.value = 值；this.year = 年；}公共财产(){pCode = "";值 = 0;年 = 0;}公共抽象无效折旧()；//存取器私人字符串 getCode(){返回代码；}私人双 getValue(){返回值；}私人 int getYear(){回归年份；}//突变体私有无效集代码(字符串新代码){this.pCode = 新代码；}私有无效集值(双新值){this.value = newValue;}私有无效 setYear(int newYear){this.year = newYear;}公共字符串 toString(){return ("代码:" + getCode() + "
Value:" + getValue() + "
Year:" + getYear());}}

这是Houses

的代码

public class Houses extends Property{内部卧室；内部楼层；公共房屋(){极好的();//调用构造函数这.卧室= 0;this.storeys = 0;}公共房屋(字符串 pCode，双值，整数年，整数卧室，整数楼层){超级(代码，价值，年)；this.bedrooms = 卧室；this.storeys = 楼层数；}//访问器私人 int getBedrooms(){返回卧室；}私人 int getStoreys(){返回楼层；}私人空间 setBedrooms(int 卧室){this.bedrooms = 卧室；}私有无效 setStoreys(int storeys){this.storeys = 楼层数；}公共无效折旧(){this.value = 95/100 * super.value;System.out.println(this.value);}公共字符串 toString(){返回 (super.toString() + "卧室:" + getBedrooms() + "Storeys:" + getStoreys());}}

我现在的问题是，在方法 depreciation 中，每当我尝试在 main 方法中运行它时，如下所示

 public static void main(String[] args) {房屋 newHouses = new Houses("111",20.11,1992,4,2);newHouses.depreciation();}

它打印出 0.0 .为什么不打印 20.11 ?我该如何解决?

================================================/p>

已感谢您修复我的愚蠢错误>.<

但是，我们可以说我的财产正在使用

 私有字符串 pCode；私人双重价值；私人整数年；

现在我无法访问它们，因为它们是私人访问，还有其他方法可以访问它们吗?

解决方案

那是因为 95/100 是一个整数除法，结果是 0.试试

0.95 * super.value

或

95.0/100 * super.value

So I have two classes: Property and Houses. Property is the abstract super class and Houses is its subclass.

Here is the code for Property

public abstract class Property{
     String pCode;
     double value;
    int year;

    public Property(String pCode, double value , int year){
        this.pCode = pCode;
        this.value = value;
        this.year = year;
    }

        public Property(){
            pCode = "";
            value = 0;
            year = 0;
        }
    public abstract void depreciation();

    //Accessors
    private String getCode(){
        return pCode;
    }
    private double getValue(){
        return value;
    }
    private int getYear(){
        return year;
    }
    //Mutators
    private void setCode(String newCode){
        this.pCode = newCode;
    }
    private void setValue(double newValue){
        this.value = newValue;
    }
    private void setYear(int newYear){
        this.year = newYear;
    }

    public String toString(){
        return ("Code: " + getCode() + "
Value: " + getValue() + "
Year: " + getYear());
    }
}

Here is the code for Houses

public class Houses extends Property{
    int bedrooms;
    int storeys;


    public Houses(){
        super(); // call constructor
        this.bedrooms = 0;
        this.storeys = 0;
    }

    public Houses(String pCode , double value , int year ,int bedrooms , int storeys){
                super(pCode,value,year);
        this.bedrooms = bedrooms;
        this.storeys = storeys;
    }
    //accessors
    private int getBedrooms(){
        return bedrooms;
    }
    private int getStoreys(){
        return storeys;
    }
    private void setBedrooms(int bedrooms){
        this.bedrooms = bedrooms;
    }
    private void setStoreys(int storeys){
        this.storeys = storeys;
    }

    public void depreciation(){

            this.value = 95 / 100 * super.value;
            System.out.println(this.value);
    }
        public String toString(){
        return (super.toString() + "Bedroom:" + getBedrooms() + "Storeys:" + getStoreys());
    }

}

My problem now is that in the method depreciation, whenever I try to run it in the main method like the following

    public static void main(String[] args) {
        Houses newHouses = new Houses("111",20.11,1992,4,2);
        newHouses.depreciation();
     }

it prints out 0.0 . Why is it not printing 20.11 ? And how do I fix it?

==============================================

Edited : Thanks for fixing my silly error >.<

However lets just say my property were using

          private String pCode;
          private double value;  
          private int year;

now I'm not able to access them because they are private access, is there any other way to access them ?

解决方案

That's because 95 / 100 is an integer division which yields 0 as a result. Try with

0.95 * super.value

or

95.0 / 100 * super.value

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