How to access Abstract superclass instance variabl

2019-03-06 19:56发布

问题:

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() + "\nValue: " + getValue() + "\nYear: " + 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 ?

回答1:

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


回答2:

Instead of:

 this.value = 95 / 100 * super.value;

you should have:

 this.value = 95d / 100d * super.value;

95/100 results in the int value of 0.



回答3:

On my phone, so I can't do appropriate code blocks, but here it goes.

private int x;

public int getX() {
    return x;
}