小编eng*_*ngy的帖子

我有这4个java clases:1

public class Rect {
    double width;
    double height;
    String color;

    public Rect( ) {
        width=0;
        height=0;
        color="transparent";      
    }

    public Rect( double w,double h) {
        width=w;
        height=h;
        color="transparent";
    }

    double area()
    {
        return  width*height;
    } 
}

2

public class PRect extends Rect{
    double depth;

    public PRect(double w, double h ,double d) {
        width=w;
        height=h;
        depth=d;
    }

    double area()
    {
        return  width*height*depth;
    }     
}

3

public class CRect extends Rect{ 
    String color;

    public CRect(double w, double h ,String c) { …