ex4-5.java

public class Shape {
    //private instance variables
    private String colour;
    private boolean filled;

    //constructors
    public Shape() {
        this.colour = "red";
        this.filled = true;

        System.out.println("Constructed a Shape with Shape()");
    }

    public Shape(String colour, boolean filled) {
        this.colour = colour;
        this.filled = filled;
    }

    public String getColour() {
        return colour;
    }

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

    public boolean isFilled() {
        return filled;
    }

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

    public String toString() {
        return  "Shape[colour =" + colour + ", filled =" + filled + "]";
    }
}

//next class

public class Circle extends Shape {
    //private instance variable
    private double radius;

    //constructors
    public Circle() {
        super(); //to invoke superclass' constructor Shape()
        this.radius = 1.0;

        System.out.println("Constructed a Circle with Circle()"); //for debugging
    }

    public Circle(double radius) {
        super();
        this.radius = radius;

        System.out.println("Constructed a Circle with Circle()"); //for debugging
    }

    public Circle(double radius, String colour, boolean filled) {
        super(colour, filled);
        this.radius = radius;

        System.out.println("Constructed a Circle with Circle()"); //for debugging
    }

    //getters and setters

    public double getRadius() {
        return radius;
    }

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

    //returns the area of the circle
    public double getArea() {
        return radius * radius * Math.PI;
    }

    //returns the circumference of the circle
    public double getPerimeter() {
        return 2 * Math.PI * radius;
    }

    //overrides inherited toString()
    @Override
    public String toString() {
        return "Circle[" + super.toString() + ", radius =" + radius + "]";
    }
}

//next class
public class Rectangle extends Shape {
    //private instance variables
    private double width;
    private double length;

    //constructors
    public Rectangle() {
        super(); //invokes the superclass
        this.width = 1.0;
        this.length = 1.0;

        System.out.println("Constructed a Rectangle with Rectangle()"); //for debugging
    }

    public Rectangle(double width, double length) {
        super(); //invokes the superclass
        this.width = width;
        this.length = length;

        System.out.println("Constructed a Rectangle with Rectangle()"); //for debugging
    }

    public Rectangle(double width, double length, String colour, boolean filled) {
        super(colour, filled); //invokes the superclass
        this.width = width;
        this.length = length;

        System.out.println("Constructed a Rectangle with Rectangle()"); //for debugging
    }

    //getters and setters
    public double getWidth() {
        return width;
    }

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

    public double getLength() {
        return length;
    }

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

    //returns the area of the rectangle
    public double getArea() {
        return width * length;
    }

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

    @Override
    public String toString() {
        return "Rectangle[" + super.toString() + ", width =" + width + ", length =" + length + "]";
    }
}

// next class
public class Square extends Rectangle {
    private double side;
    //constructors
    public Square() {
        super();
    }

    public Square(double side) {
        super(side, side);
    }

    public Square(double side, String colour, boolean filled) {
        super(side, side, colour, filled);
    }

    public double getSide() {
        return side;
    }

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

    public void setWidth(double side) {
    }

    public void setLength(double side) {
    }

    @Override
    public String toString() {
        return "Square[" + super.toString() + "]";
    }
}

// test class
public class testShape {
    public static void main(String[] args) {

        //to test circle class
        Circle c1 = new Circle();
        c1.setRadius(1.0);
        c1.setColour("red");
        c1.setFilled(true);

        System.out.println(c1);

        System.out.println("Area is " + c1.getArea() + ", Perimeter is " + c1.getPerimeter());

        System.out.println(); //blank print statement to make output look neater

        //to test rectangle class
        Rectangle r1 = new Rectangle();
        r1.setWidth(1.0);
        r1.setLength(1.0);
        r1.setColour("blue");
        r1.setFilled(true);

        System.out.println(r1);

        System.out.println("Area is " + r1.getArea() + ", Perimeter is " + r1.getPerimeter());

        System.out.println();

        //to test square class
        Square s1 = new Square();
        s1.setSide(1.0);
        s1.setSide(1.0);
        s1.setColour("green");
        s1.setFilled(true);

        System.out.println(s1);

        System.out.println("Area is " + r1.getArea() + ", Perimeter is " + r1.getPerimeter());
    }
}


//i do not care if its correct or not, this is just for archiving purposes