在画图软件中，可以画出不同大小或颜色的圆形、矩形等几何图形。几何图形之间有许多共同的特征，如它们可以是用某种颜色画出来的，可以是填充的或者不填充的。

//抽象类 图形类
public abstract class Graphical {

        private String colour;
        private boolean fill;

        public abstract double perimeter();
        public abstract double area();
        public abstract String toString() ;


        public Graphical() {

        }
        public Graphical(String colour, boolean fill) {
            this.colour = colour;
            this.fill = fill;
        }

        public String getColour() {
            return colour;
        }

        public void setColour(String colour) {
            this.colour = colour;
        }

        public boolean isFill() {
            return fill;
        }

        public void setFill(boolean fill) {
            this.fill = fill;
        }


}

//正方形类
public class Square extends Graphical{
    private double side;

    public Square(String colour, boolean fill, double side) {
        super(colour, fill);
        this.side = side;
    }

    public double getSide() {
        return side;
    }

    public void setSide(double side) {
        this.side = side;
    }

    public double perimeter() {
        return 2*side;
    }


    public double area() {
        return side*side;
    }


    public String toString() {
      return   "正方形的颜色为："+getColour()+"\t有无填充："+isFill()+"边长为："+getSide()+"周长为："+perimeter()+"面积为："+area();
    }
}

//长方形类
public class Rectangle extends Graphical{
    private double length;
    private double width;

    public Rectangle(String colour, boolean fill, double length,double width) {
        super(colour, fill);
        this.length = length;
        this.width=  width;
    }

    public double getLength() {

        return length;
    }

    public void setLength(double length) {

        this.length = length;
    }

    public double getWidth() {

        return width;
    }

    public void setWidth(double width) {

        this.width = width;
    }

    public double perimeter() {
        return (length+width)*2;
    }


    public double area() {

        return length*width;
    }

    @Override
    public String toString() {
        return "长方形的颜色为："+getColour()+"\t有无填充："+isFill()+"长为："+getLength()+"宽为："+getWidth()+"周长为："+perimeter()+"面积为："+area();
    }
}

//子类 圆形类
public class Circular extends Graphical {
    private double R;

    public Circular(String colour, boolean fill, double r) {
        super(colour, fill);
        R = r;
    }

    public double getR() {
        return R;
    }

    public void setR(double r) {
        R = r;
    }

    public double perimeter() {
        return R*2*3.14;
    }


    public double area() {
        return R*R*3.14;
    }



    public String toString() {
        return "圆的颜色为：" +getColour() +"\t"+"有无填充:" +isFill()+ "半径为："+getR()+"的圆形面积为："+area()+"周长为："+perimeter() ;
    }
}

//测试类
public class Text {
    public static void main(String[] args) {
        Circular circular=new Circular("绿色",true,3.0);
        System.out.println(circular.toString());
        
        Rectangle rectangle=new Rectangle("红色",false,10.0,5.0);
        System.out.println(rectangle.toString());
        
        Square square=new Square("黄色",false,4.0);
        System.out.println(square.toString());
    }
}