T3

public abstract class Shape {
    protected String color;
    protected boolean filled;

    public Shape(String c, boolean f){
        this.color = c;
        this.filled = f;
    }

    public Shape(){
        this("None", false);
    }

    public void setColor(String color) {
        this.color = color;
    }

    public String getColor() {
        return color;
    }

    public boolean isFilled() {
        return filled;
    }

    public void setFilled(boolean filled) {
        this.filled = filled;
    }

    public abstract double getArea();
    public abstract double getPerimeter();
    public abstract String ToString();
}

////////////////////////
public class Circle extends Shape {
    protected double radius;
    public Circle(double radius, String color, boolean filled){
        super(color, filled);
        this.radius = radius;
    }

    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }

    @Override
    public double getArea() {
        return 2*Math.PI*(radius*radius);
    }

    @Override
    public double getPerimeter() {
        return 2*Math.PI*radius;
    }

    @Override
    public String ToString() {
        return "Радиус: " + String.valueOf(this.getRadius()) + "\nПлощадь: " + String.valueOf(this.getArea()) + "\nПериметр: " + String.valueOf(this.getPerimeter())
                + "\nЦвет: " + color + "\nПрозрачность: " + filled;
    }
}

/////////////////////////
public class Rectangle extends Shape {
    protected double width;
    protected double length;

    public Rectangle(double w, double l){
        super();
        width = w;
        length = l;
    }

    public Rectangle(double w, double l, String color, boolean fill){
        super(color, fill);
        width = w;
        length = l;
    }

    public Rectangle(){
        width = 1;
        length = 1;
    }

    public double getLength() {
        return length;
    }

    public double getWidth() {
        return width;
    }

    public void setLength(double length) {
        this.length = length;
    }

    public void setWidth(double width) {
        this.width = width;
    }

    @Override
    public double getArea(){
        return width*length;
    }

    @Override
    public double getPerimeter(){
        return (2*width)+(2*length);
    }

    @Override
    public String ToString(){
       return "Длина: " + length + "\nШирина: " + width + "\nПлощадь: " +this.getArea() + "\nПериметр: " + this.getPerimeter();
    }
}

///////////////////////////
public class Square extends Rectangle {
    protected double side;
    public Square(double si) {super(si, si); side = si;}

    @Override
    public double getArea(){
        return width*length;
    }

    @Override
    public double getPerimeter(){
        return (2*width)+(2*length);
    }

    @Override
    public double getWidth() {
        return side;
    }
    public double getSide() {
        return side;
    }

    @Override
    public String ToString(){
        return "Длина: " + length + "\nШирина: " + width + "\nПлощадь: " +String.valueOf(this.getArea()) + "\nПериметр: " + String.valueOf(this.getPerimeter());
    }
}

/////////////////////////
public class Main {
    public static void main(String[] args){
        Shape s1 = new Circle(5.5, "RED", false); // Upcast Circle to Shape
        System.out.println(s1); // which version?
        System.out.println(s1.getArea()); // which version?
        System.out.println(s1.getPerimeter()); // which version?
        System.out.println(s1.getColor());
        System.out.println(s1.isFilled());
        //System.out.println(s1.getRadius());

        Circle c1 = (Circle)s1; // Downcast back to Circle
        System.out.println(c1);
        System.out.println(c1.getArea());
        System.out.println(c1.getPerimeter());
        System.out.println(c1.getColor());
        System.out.println(c1.isFilled());
        System.out.println(c1.getRadius());

        //Shape s2 = new Shape();

        Shape s3 = new Rectangle(1.0, 2.0, "RED", false); // Upcast
        System.out.println(s3);
        System.out.println(s3.getArea());
        System.out.println(s3.getPerimeter());
        System.out.println(s3.getColor());
        //System.out.println(s3.getLength());

        Rectangle r1 = (Rectangle)s3; // downcast
        System.out.println(r1);
        System.out.println(r1.getArea());
        System.out.println(r1.getColor());
        System.out.println(r1.getLength());

        Shape s4 = new Square(6.6); // Upcast
        System.out.println(s4);
        System.out.println(s4.getArea());
        System.out.println(s4.getColor());
        //System.out.println(s4.getSide());

// Take note that we downcast Shape s4 to Rectangle,
// which is a superclass of Square, instead of Square
        Rectangle r2 = (Rectangle)s4;
        System.out.println(r2);
        System.out.println(r2.getArea());
        System.out.println(r2.getColor());
        //System.out.println(r2.getSide());
        System.out.println(r2.getLength());

// Downcast Rectangle r2 to Square
        Square sq1 = (Square)r2;
        System.out.println(sq1);
        System.out.println(sq1.getArea());
        System.out.println(sq1.getColor());
        System.out.println(sq1.getSide());
        System.out.println(sq1.getLength());
    }
}